1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2017 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
28 #include "tree-pass.h"
31 #include "diagnostic-core.h"
32 #include "fold-const.h"
36 #include "cfgcleanup.h"
38 #include "gimple-iterator.h"
40 #include "tree-into-ssa.h"
42 #include "tree-inline.h"
43 #include "langhooks.h"
45 #include "gimple-low.h"
48 /* In some instances a tree and a gimple need to be stored in a same table,
49 i.e. in hash tables. This is a structure to do this. */
50 typedef union {tree
*tp
; tree t
; gimple
*g
;} treemple
;
52 /* Misc functions used in this file. */
54 /* Remember and lookup EH landing pad data for arbitrary statements.
55 Really this means any statement that could_throw_p. We could
56 stuff this information into the stmt_ann data structure, but:
58 (1) We absolutely rely on this information being kept until
59 we get to rtl. Once we're done with lowering here, if we lose
60 the information there's no way to recover it!
62 (2) There are many more statements that *cannot* throw as
63 compared to those that can. We should be saving some amount
64 of space by only allocating memory for those that can throw. */
66 /* Add statement T in function IFUN to landing pad NUM. */
69 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple
*t
, int num
)
71 gcc_assert (num
!= 0);
73 if (!get_eh_throw_stmt_table (ifun
))
74 set_eh_throw_stmt_table (ifun
, hash_map
<gimple
*, int>::create_ggc (31));
76 gcc_assert (!get_eh_throw_stmt_table (ifun
)->put (t
, num
));
79 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
82 add_stmt_to_eh_lp (gimple
*t
, int num
)
84 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
87 /* Add statement T to the single EH landing pad in REGION. */
90 record_stmt_eh_region (eh_region region
, gimple
*t
)
94 if (region
->type
== ERT_MUST_NOT_THROW
)
95 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
98 eh_landing_pad lp
= region
->landing_pads
;
100 lp
= gen_eh_landing_pad (region
);
102 gcc_assert (lp
->next_lp
== NULL
);
103 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
108 /* Remove statement T in function IFUN from its EH landing pad. */
111 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple
*t
)
113 if (!get_eh_throw_stmt_table (ifun
))
116 if (!get_eh_throw_stmt_table (ifun
)->get (t
))
119 get_eh_throw_stmt_table (ifun
)->remove (t
);
124 /* Remove statement T in the current function (cfun) from its
128 remove_stmt_from_eh_lp (gimple
*t
)
130 return remove_stmt_from_eh_lp_fn (cfun
, t
);
133 /* Determine if statement T is inside an EH region in function IFUN.
134 Positive numbers indicate a landing pad index; negative numbers
135 indicate a MUST_NOT_THROW region index; zero indicates that the
136 statement is not recorded in the region table. */
139 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple
*t
)
141 if (ifun
->eh
->throw_stmt_table
== NULL
)
144 int *lp_nr
= ifun
->eh
->throw_stmt_table
->get (t
);
145 return lp_nr
? *lp_nr
: 0;
148 /* Likewise, but always use the current function. */
151 lookup_stmt_eh_lp (gimple
*t
)
153 /* We can get called from initialized data when -fnon-call-exceptions
154 is on; prevent crash. */
157 return lookup_stmt_eh_lp_fn (cfun
, t
);
160 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
161 nodes and LABEL_DECL nodes. We will use this during the second phase to
162 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
164 struct finally_tree_node
166 /* When storing a GIMPLE_TRY, we have to record a gimple. However
167 when deciding whether a GOTO to a certain LABEL_DECL (which is a
168 tree) leaves the TRY block, its necessary to record a tree in
169 this field. Thus a treemple is used. */
174 /* Hashtable helpers. */
176 struct finally_tree_hasher
: free_ptr_hash
<finally_tree_node
>
178 static inline hashval_t
hash (const finally_tree_node
*);
179 static inline bool equal (const finally_tree_node
*,
180 const finally_tree_node
*);
184 finally_tree_hasher::hash (const finally_tree_node
*v
)
186 return (intptr_t)v
->child
.t
>> 4;
190 finally_tree_hasher::equal (const finally_tree_node
*v
,
191 const finally_tree_node
*c
)
193 return v
->child
.t
== c
->child
.t
;
196 /* Note that this table is *not* marked GTY. It is short-lived. */
197 static hash_table
<finally_tree_hasher
> *finally_tree
;
200 record_in_finally_tree (treemple child
, gtry
*parent
)
202 struct finally_tree_node
*n
;
203 finally_tree_node
**slot
;
205 n
= XNEW (struct finally_tree_node
);
209 slot
= finally_tree
->find_slot (n
, INSERT
);
215 collect_finally_tree (gimple
*stmt
, gtry
*region
);
217 /* Go through the gimple sequence. Works with collect_finally_tree to
218 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
221 collect_finally_tree_1 (gimple_seq seq
, gtry
*region
)
223 gimple_stmt_iterator gsi
;
225 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
226 collect_finally_tree (gsi_stmt (gsi
), region
);
230 collect_finally_tree (gimple
*stmt
, gtry
*region
)
234 switch (gimple_code (stmt
))
237 temp
.t
= gimple_label_label (as_a
<glabel
*> (stmt
));
238 record_in_finally_tree (temp
, region
);
242 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
245 record_in_finally_tree (temp
, region
);
246 collect_finally_tree_1 (gimple_try_eval (stmt
),
247 as_a
<gtry
*> (stmt
));
248 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
250 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
252 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
253 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
258 collect_finally_tree_1 (gimple_catch_handler (
259 as_a
<gcatch
*> (stmt
)),
263 case GIMPLE_EH_FILTER
:
264 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
269 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
270 collect_finally_tree_1 (gimple_eh_else_n_body (eh_else_stmt
), region
);
271 collect_finally_tree_1 (gimple_eh_else_e_body (eh_else_stmt
), region
);
276 /* A type, a decl, or some kind of statement that we're not
277 interested in. Don't walk them. */
283 /* Use the finally tree to determine if a jump from START to TARGET
284 would leave the try_finally node that START lives in. */
287 outside_finally_tree (treemple start
, gimple
*target
)
289 struct finally_tree_node n
, *p
;
294 p
= finally_tree
->find (&n
);
299 while (start
.g
!= target
);
304 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
305 nodes into a set of gotos, magic labels, and eh regions.
306 The eh region creation is straight-forward, but frobbing all the gotos
307 and such into shape isn't. */
309 /* The sequence into which we record all EH stuff. This will be
310 placed at the end of the function when we're all done. */
311 static gimple_seq eh_seq
;
313 /* Record whether an EH region contains something that can throw,
314 indexed by EH region number. */
315 static bitmap eh_region_may_contain_throw_map
;
317 /* The GOTO_QUEUE is an array of GIMPLE_GOTO and GIMPLE_RETURN
318 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
319 The idea is to record a gimple statement for everything except for
320 the conditionals, which get their labels recorded. Since labels are
321 of type 'tree', we need this node to store both gimple and tree
322 objects. REPL_STMT is the sequence used to replace the goto/return
323 statement. CONT_STMT is used to store the statement that allows
324 the return/goto to jump to the original destination. */
326 struct goto_queue_node
330 gimple_seq repl_stmt
;
333 /* This is used when index >= 0 to indicate that stmt is a label (as
334 opposed to a goto stmt). */
338 /* State of the world while lowering. */
342 /* What's "current" while constructing the eh region tree. These
343 correspond to variables of the same name in cfun->eh, which we
344 don't have easy access to. */
345 eh_region cur_region
;
347 /* What's "current" for the purposes of __builtin_eh_pointer. For
348 a CATCH, this is the associated TRY. For an EH_FILTER, this is
349 the associated ALLOWED_EXCEPTIONS, etc. */
350 eh_region ehp_region
;
352 /* Processing of TRY_FINALLY requires a bit more state. This is
353 split out into a separate structure so that we don't have to
354 copy so much when processing other nodes. */
355 struct leh_tf_state
*tf
;
360 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
361 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
362 this so that outside_finally_tree can reliably reference the tree used
363 in the collect_finally_tree data structures. */
364 gtry
*try_finally_expr
;
367 /* While lowering a top_p usually it is expanded into multiple statements,
368 thus we need the following field to store them. */
369 gimple_seq top_p_seq
;
371 /* The state outside this try_finally node. */
372 struct leh_state
*outer
;
374 /* The exception region created for it. */
377 /* The goto queue. */
378 struct goto_queue_node
*goto_queue
;
379 size_t goto_queue_size
;
380 size_t goto_queue_active
;
382 /* Pointer map to help in searching goto_queue when it is large. */
383 hash_map
<gimple
*, goto_queue_node
*> *goto_queue_map
;
385 /* The set of unique labels seen as entries in the goto queue. */
386 vec
<tree
> dest_array
;
388 /* A label to be added at the end of the completed transformed
389 sequence. It will be set if may_fallthru was true *at one time*,
390 though subsequent transformations may have cleared that flag. */
393 /* True if it is possible to fall out the bottom of the try block.
394 Cleared if the fallthru is converted to a goto. */
397 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
400 /* True if the finally block can receive an exception edge.
401 Cleared if the exception case is handled by code duplication. */
405 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gtry
*);
407 /* Search for STMT in the goto queue. Return the replacement,
408 or null if the statement isn't in the queue. */
410 #define LARGE_GOTO_QUEUE 20
412 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
415 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
419 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
421 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
422 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
423 return tf
->goto_queue
[i
].repl_stmt
;
427 /* If we have a large number of entries in the goto_queue, create a
428 pointer map and use that for searching. */
430 if (!tf
->goto_queue_map
)
432 tf
->goto_queue_map
= new hash_map
<gimple
*, goto_queue_node
*>;
433 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
435 bool existed
= tf
->goto_queue_map
->put (tf
->goto_queue
[i
].stmt
.g
,
437 gcc_assert (!existed
);
441 goto_queue_node
**slot
= tf
->goto_queue_map
->get (stmt
.g
);
443 return ((*slot
)->repl_stmt
);
448 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
449 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
450 then we can just splat it in, otherwise we add the new stmts immediately
451 after the GIMPLE_COND and redirect. */
454 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
455 gimple_stmt_iterator
*gsi
)
460 location_t loc
= gimple_location (gsi_stmt (*gsi
));
463 new_seq
= find_goto_replacement (tf
, temp
);
467 if (gimple_seq_singleton_p (new_seq
)
468 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
470 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
474 label
= create_artificial_label (loc
);
475 /* Set the new label for the GIMPLE_COND */
478 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
479 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
482 /* The real work of replace_goto_queue. Returns with TSI updated to
483 point to the next statement. */
485 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
488 replace_goto_queue_1 (gimple
*stmt
, struct leh_tf_state
*tf
,
489 gimple_stmt_iterator
*gsi
)
495 switch (gimple_code (stmt
))
500 seq
= find_goto_replacement (tf
, temp
);
503 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
504 gsi_remove (gsi
, false);
510 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
511 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
515 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
516 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
519 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (
520 as_a
<gcatch
*> (stmt
)),
523 case GIMPLE_EH_FILTER
:
524 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
528 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
529 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (eh_else_stmt
),
531 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (eh_else_stmt
),
537 /* These won't have gotos in them. */
544 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
547 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
549 gimple_stmt_iterator gsi
= gsi_start (*seq
);
551 while (!gsi_end_p (gsi
))
552 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
555 /* Replace all goto queue members. */
558 replace_goto_queue (struct leh_tf_state
*tf
)
560 if (tf
->goto_queue_active
== 0)
562 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
563 replace_goto_queue_stmt_list (&eh_seq
, tf
);
566 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
567 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
571 record_in_goto_queue (struct leh_tf_state
*tf
,
578 struct goto_queue_node
*q
;
580 gcc_assert (!tf
->goto_queue_map
);
582 active
= tf
->goto_queue_active
;
583 size
= tf
->goto_queue_size
;
586 size
= (size
? size
* 2 : 32);
587 tf
->goto_queue_size
= size
;
589 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
592 q
= &tf
->goto_queue
[active
];
593 tf
->goto_queue_active
= active
+ 1;
595 memset (q
, 0, sizeof (*q
));
598 q
->location
= location
;
599 q
->is_label
= is_label
;
602 /* Record the LABEL label in the goto queue contained in TF.
606 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
610 treemple temp
, new_stmt
;
615 /* Computed and non-local gotos do not get processed. Given
616 their nature we can neither tell whether we've escaped the
617 finally block nor redirect them if we knew. */
618 if (TREE_CODE (label
) != LABEL_DECL
)
621 /* No need to record gotos that don't leave the try block. */
623 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
626 if (! tf
->dest_array
.exists ())
628 tf
->dest_array
.create (10);
629 tf
->dest_array
.quick_push (label
);
634 int n
= tf
->dest_array
.length ();
635 for (index
= 0; index
< n
; ++index
)
636 if (tf
->dest_array
[index
] == label
)
639 tf
->dest_array
.safe_push (label
);
642 /* In the case of a GOTO we want to record the destination label,
643 since with a GIMPLE_COND we have an easy access to the then/else
646 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
649 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
650 node, and if so record that fact in the goto queue associated with that
654 maybe_record_in_goto_queue (struct leh_state
*state
, gimple
*stmt
)
656 struct leh_tf_state
*tf
= state
->tf
;
662 switch (gimple_code (stmt
))
666 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
667 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 2);
668 record_in_goto_queue_label (tf
, new_stmt
,
669 gimple_cond_true_label (cond_stmt
),
670 EXPR_LOCATION (*new_stmt
.tp
));
671 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 3);
672 record_in_goto_queue_label (tf
, new_stmt
,
673 gimple_cond_false_label (cond_stmt
),
674 EXPR_LOCATION (*new_stmt
.tp
));
679 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
680 gimple_location (stmt
));
684 tf
->may_return
= true;
686 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
696 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
697 was in fact structured, and we've not yet done jump threading, then none
698 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
701 verify_norecord_switch_expr (struct leh_state
*state
,
702 gswitch
*switch_expr
)
704 struct leh_tf_state
*tf
= state
->tf
;
710 n
= gimple_switch_num_labels (switch_expr
);
712 for (i
= 0; i
< n
; ++i
)
715 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
717 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
721 #define verify_norecord_switch_expr(state, switch_expr)
724 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
725 non-null, insert it before the new branch. */
728 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
732 /* In the case of a return, the queue node must be a gimple statement. */
733 gcc_assert (!q
->is_label
);
735 /* Note that the return value may have already been computed, e.g.,
748 should return 0, not 1. We don't have to do anything to make
749 this happens because the return value has been placed in the
750 RESULT_DECL already. */
752 q
->cont_stmt
= q
->stmt
.g
;
755 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
757 x
= gimple_build_goto (finlab
);
758 gimple_set_location (x
, q
->location
);
759 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
762 /* Similar, but easier, for GIMPLE_GOTO. */
765 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
766 struct leh_tf_state
*tf
)
770 gcc_assert (q
->is_label
);
772 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
775 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
777 x
= gimple_build_goto (finlab
);
778 gimple_set_location (x
, q
->location
);
779 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
782 /* Emit a standard landing pad sequence into SEQ for REGION. */
785 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
787 eh_landing_pad lp
= region
->landing_pads
;
791 lp
= gen_eh_landing_pad (region
);
793 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
794 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
796 x
= gimple_build_label (lp
->post_landing_pad
);
797 gimple_seq_add_stmt (seq
, x
);
800 /* Emit a RESX statement into SEQ for REGION. */
803 emit_resx (gimple_seq
*seq
, eh_region region
)
805 gresx
*x
= gimple_build_resx (region
->index
);
806 gimple_seq_add_stmt (seq
, x
);
808 record_stmt_eh_region (region
->outer
, x
);
811 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
814 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
816 geh_dispatch
*x
= gimple_build_eh_dispatch (region
->index
);
817 gimple_seq_add_stmt (seq
, x
);
820 /* Note that the current EH region may contain a throw, or a
821 call to a function which itself may contain a throw. */
824 note_eh_region_may_contain_throw (eh_region region
)
826 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
828 if (region
->type
== ERT_MUST_NOT_THROW
)
830 region
= region
->outer
;
836 /* Check if REGION has been marked as containing a throw. If REGION is
837 NULL, this predicate is false. */
840 eh_region_may_contain_throw (eh_region r
)
842 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
845 /* We want to transform
846 try { body; } catch { stuff; }
856 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
857 should be placed before the second operand, or NULL. OVER is
858 an existing label that should be put at the exit, or NULL. */
861 frob_into_branch_around (gtry
*tp
, eh_region region
, tree over
)
864 gimple_seq cleanup
, result
;
865 location_t loc
= gimple_location (tp
);
867 cleanup
= gimple_try_cleanup (tp
);
868 result
= gimple_try_eval (tp
);
871 emit_post_landing_pad (&eh_seq
, region
);
873 if (gimple_seq_may_fallthru (cleanup
))
876 over
= create_artificial_label (loc
);
877 x
= gimple_build_goto (over
);
878 gimple_set_location (x
, loc
);
879 gimple_seq_add_stmt (&cleanup
, x
);
881 gimple_seq_add_seq (&eh_seq
, cleanup
);
885 x
= gimple_build_label (over
);
886 gimple_seq_add_stmt (&result
, x
);
891 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
892 Make sure to record all new labels found. */
895 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
900 gimple_stmt_iterator gsi
;
902 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
904 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
906 gimple
*stmt
= gsi_stmt (gsi
);
907 /* We duplicate __builtin_stack_restore at -O0 in the hope of eliminating
908 it on the EH paths. When it is not eliminated, make it transparent in
910 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
911 gimple_set_location (stmt
, UNKNOWN_LOCATION
);
912 else if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
914 tree block
= gimple_block (stmt
);
915 gimple_set_location (stmt
, loc
);
916 gimple_set_block (stmt
, block
);
921 region
= outer_state
->tf
->try_finally_expr
;
922 collect_finally_tree_1 (new_seq
, region
);
927 /* A subroutine of lower_try_finally. Create a fallthru label for
928 the given try_finally state. The only tricky bit here is that
929 we have to make sure to record the label in our outer context. */
932 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
934 tree label
= tf
->fallthru_label
;
939 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
940 tf
->fallthru_label
= label
;
944 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
950 /* A subroutine of lower_try_finally. If FINALLY consits of a
951 GIMPLE_EH_ELSE node, return it. */
953 static inline geh_else
*
954 get_eh_else (gimple_seq finally
)
956 gimple
*x
= gimple_seq_first_stmt (finally
);
957 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
959 gcc_assert (gimple_seq_singleton_p (finally
));
960 return as_a
<geh_else
*> (x
);
965 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
966 langhook returns non-null, then the language requires that the exception
967 path out of a try_finally be treated specially. To wit: the code within
968 the finally block may not itself throw an exception. We have two choices
969 here. First we can duplicate the finally block and wrap it in a
970 must_not_throw region. Second, we can generate code like
975 if (fintmp == eh_edge)
976 protect_cleanup_actions;
979 where "fintmp" is the temporary used in the switch statement generation
980 alternative considered below. For the nonce, we always choose the first
983 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
986 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
987 struct leh_state
*this_state
,
988 struct leh_tf_state
*tf
)
990 gimple_seq finally
= gimple_try_cleanup (tf
->top_p
);
992 /* EH_ELSE doesn't come from user code; only compiler generated stuff.
993 It does need to be handled here, so as to separate the (different)
994 EH path from the normal path. But we should not attempt to wrap
995 it with a must-not-throw node (which indeed gets in the way). */
996 if (geh_else
*eh_else
= get_eh_else (finally
))
998 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
999 finally
= gimple_eh_else_e_body (eh_else
);
1001 /* Let the ELSE see the exception that's being processed. */
1002 eh_region save_ehp
= this_state
->ehp_region
;
1003 this_state
->ehp_region
= this_state
->cur_region
;
1004 lower_eh_constructs_1 (this_state
, &finally
);
1005 this_state
->ehp_region
= save_ehp
;
1009 /* First check for nothing to do. */
1010 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1012 tree actions
= lang_hooks
.eh_protect_cleanup_actions ();
1013 if (actions
== NULL
)
1017 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1018 gimple_location (tf
->try_finally_expr
));
1020 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1021 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1022 to be in an enclosing scope, but needs to be implemented at this level
1023 to avoid a nesting violation (see wrap_temporary_cleanups in
1024 cp/decl.c). Since it's logically at an outer level, we should call
1025 terminate before we get to it, so strip it away before adding the
1026 MUST_NOT_THROW filter. */
1027 gimple_stmt_iterator gsi
= gsi_start (finally
);
1028 gimple
*x
= gsi_stmt (gsi
);
1029 if (gimple_code (x
) == GIMPLE_TRY
1030 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1031 && gimple_try_catch_is_cleanup (x
))
1033 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1034 gsi_remove (&gsi
, false);
1037 /* Wrap the block with protect_cleanup_actions as the action. */
1038 geh_mnt
*eh_mnt
= gimple_build_eh_must_not_throw (actions
);
1039 gtry
*try_stmt
= gimple_build_try (finally
,
1040 gimple_seq_alloc_with_stmt (eh_mnt
),
1042 finally
= lower_eh_must_not_throw (outer_state
, try_stmt
);
1045 /* Drop all of this into the exception sequence. */
1046 emit_post_landing_pad (&eh_seq
, tf
->region
);
1047 gimple_seq_add_seq (&eh_seq
, finally
);
1048 if (gimple_seq_may_fallthru (finally
))
1049 emit_resx (&eh_seq
, tf
->region
);
1051 /* Having now been handled, EH isn't to be considered with
1052 the rest of the outgoing edges. */
1053 tf
->may_throw
= false;
1056 /* A subroutine of lower_try_finally. We have determined that there is
1057 no fallthru edge out of the finally block. This means that there is
1058 no outgoing edge corresponding to any incoming edge. Restructure the
1059 try_finally node for this special case. */
1062 lower_try_finally_nofallthru (struct leh_state
*state
,
1063 struct leh_tf_state
*tf
)
1069 struct goto_queue_node
*q
, *qe
;
1071 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1073 /* We expect that tf->top_p is a GIMPLE_TRY. */
1074 finally
= gimple_try_cleanup (tf
->top_p
);
1075 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1077 x
= gimple_build_label (lab
);
1078 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1081 qe
= q
+ tf
->goto_queue_active
;
1084 do_return_redirection (q
, lab
, NULL
);
1086 do_goto_redirection (q
, lab
, NULL
, tf
);
1088 replace_goto_queue (tf
);
1090 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1091 eh_else
= get_eh_else (finally
);
1094 finally
= gimple_eh_else_n_body (eh_else
);
1095 lower_eh_constructs_1 (state
, &finally
);
1096 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1100 finally
= gimple_eh_else_e_body (eh_else
);
1101 lower_eh_constructs_1 (state
, &finally
);
1103 emit_post_landing_pad (&eh_seq
, tf
->region
);
1104 gimple_seq_add_seq (&eh_seq
, finally
);
1109 lower_eh_constructs_1 (state
, &finally
);
1110 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1114 emit_post_landing_pad (&eh_seq
, tf
->region
);
1116 x
= gimple_build_goto (lab
);
1117 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1118 gimple_seq_add_stmt (&eh_seq
, x
);
1123 /* A subroutine of lower_try_finally. We have determined that there is
1124 exactly one destination of the finally block. Restructure the
1125 try_finally node for this special case. */
1128 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1130 struct goto_queue_node
*q
, *qe
;
1135 gimple_stmt_iterator gsi
;
1137 location_t loc
= gimple_location (tf
->try_finally_expr
);
1139 finally
= gimple_try_cleanup (tf
->top_p
);
1140 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1142 /* Since there's only one destination, and the destination edge can only
1143 either be EH or non-EH, that implies that all of our incoming edges
1144 are of the same type. Therefore we can lower EH_ELSE immediately. */
1145 eh_else
= get_eh_else (finally
);
1149 finally
= gimple_eh_else_e_body (eh_else
);
1151 finally
= gimple_eh_else_n_body (eh_else
);
1154 lower_eh_constructs_1 (state
, &finally
);
1156 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1158 gimple
*stmt
= gsi_stmt (gsi
);
1159 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1161 tree block
= gimple_block (stmt
);
1162 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1163 gimple_set_block (stmt
, block
);
1169 /* Only reachable via the exception edge. Add the given label to
1170 the head of the FINALLY block. Append a RESX at the end. */
1171 emit_post_landing_pad (&eh_seq
, tf
->region
);
1172 gimple_seq_add_seq (&eh_seq
, finally
);
1173 emit_resx (&eh_seq
, tf
->region
);
1177 if (tf
->may_fallthru
)
1179 /* Only reachable via the fallthru edge. Do nothing but let
1180 the two blocks run together; we'll fall out the bottom. */
1181 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1185 finally_label
= create_artificial_label (loc
);
1186 label_stmt
= gimple_build_label (finally_label
);
1187 gimple_seq_add_stmt (&tf
->top_p_seq
, label_stmt
);
1189 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1192 qe
= q
+ tf
->goto_queue_active
;
1196 /* Reachable by return expressions only. Redirect them. */
1198 do_return_redirection (q
, finally_label
, NULL
);
1199 replace_goto_queue (tf
);
1203 /* Reachable by goto expressions only. Redirect them. */
1205 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1206 replace_goto_queue (tf
);
1208 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1210 /* Reachable by goto to fallthru label only. Redirect it
1211 to the new label (already created, sadly), and do not
1212 emit the final branch out, or the fallthru label. */
1213 tf
->fallthru_label
= NULL
;
1218 /* Place the original return/goto to the original destination
1219 immediately after the finally block. */
1220 x
= tf
->goto_queue
[0].cont_stmt
;
1221 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1222 maybe_record_in_goto_queue (state
, x
);
1225 /* A subroutine of lower_try_finally. There are multiple edges incoming
1226 and outgoing from the finally block. Implement this by duplicating the
1227 finally block for every destination. */
1230 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1233 gimple_seq new_stmt
;
1238 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1240 finally
= gimple_try_cleanup (tf
->top_p
);
1242 /* Notice EH_ELSE, and simplify some of the remaining code
1243 by considering FINALLY to be the normal return path only. */
1244 eh_else
= get_eh_else (finally
);
1246 finally
= gimple_eh_else_n_body (eh_else
);
1248 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1251 if (tf
->may_fallthru
)
1253 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1254 lower_eh_constructs_1 (state
, &seq
);
1255 gimple_seq_add_seq (&new_stmt
, seq
);
1257 tmp
= lower_try_finally_fallthru_label (tf
);
1258 x
= gimple_build_goto (tmp
);
1259 gimple_set_location (x
, tf_loc
);
1260 gimple_seq_add_stmt (&new_stmt
, x
);
1265 /* We don't need to copy the EH path of EH_ELSE,
1266 since it is only emitted once. */
1268 seq
= gimple_eh_else_e_body (eh_else
);
1270 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1271 lower_eh_constructs_1 (state
, &seq
);
1273 emit_post_landing_pad (&eh_seq
, tf
->region
);
1274 gimple_seq_add_seq (&eh_seq
, seq
);
1275 emit_resx (&eh_seq
, tf
->region
);
1280 struct goto_queue_node
*q
, *qe
;
1281 int return_index
, index
;
1284 struct goto_queue_node
*q
;
1288 return_index
= tf
->dest_array
.length ();
1289 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1292 qe
= q
+ tf
->goto_queue_active
;
1295 index
= q
->index
< 0 ? return_index
: q
->index
;
1297 if (!labels
[index
].q
)
1298 labels
[index
].q
= q
;
1301 for (index
= 0; index
< return_index
+ 1; index
++)
1305 q
= labels
[index
].q
;
1309 lab
= labels
[index
].label
1310 = create_artificial_label (tf_loc
);
1312 if (index
== return_index
)
1313 do_return_redirection (q
, lab
, NULL
);
1315 do_goto_redirection (q
, lab
, NULL
, tf
);
1317 x
= gimple_build_label (lab
);
1318 gimple_seq_add_stmt (&new_stmt
, x
);
1320 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1321 lower_eh_constructs_1 (state
, &seq
);
1322 gimple_seq_add_seq (&new_stmt
, seq
);
1324 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1325 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1328 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1332 index
= q
->index
< 0 ? return_index
: q
->index
;
1334 if (labels
[index
].q
== q
)
1337 lab
= labels
[index
].label
;
1339 if (index
== return_index
)
1340 do_return_redirection (q
, lab
, NULL
);
1342 do_goto_redirection (q
, lab
, NULL
, tf
);
1345 replace_goto_queue (tf
);
1349 /* Need to link new stmts after running replace_goto_queue due
1350 to not wanting to process the same goto stmts twice. */
1351 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1354 /* A subroutine of lower_try_finally. There are multiple edges incoming
1355 and outgoing from the finally block. Implement this by instrumenting
1356 each incoming edge and creating a switch statement at the end of the
1357 finally block that branches to the appropriate destination. */
1360 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1362 struct goto_queue_node
*q
, *qe
;
1363 tree finally_tmp
, finally_label
;
1364 int return_index
, eh_index
, fallthru_index
;
1365 int nlabels
, ndests
, j
, last_case_index
;
1367 auto_vec
<tree
> case_label_vec
;
1368 gimple_seq switch_body
= NULL
;
1372 gimple
*switch_stmt
;
1374 hash_map
<tree
, gimple
*> *cont_map
= NULL
;
1375 /* The location of the TRY_FINALLY stmt. */
1376 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1377 /* The location of the finally block. */
1378 location_t finally_loc
;
1380 finally
= gimple_try_cleanup (tf
->top_p
);
1381 eh_else
= get_eh_else (finally
);
1383 /* Mash the TRY block to the head of the chain. */
1384 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1386 /* The location of the finally is either the last stmt in the finally
1387 block or the location of the TRY_FINALLY itself. */
1388 x
= gimple_seq_last_stmt (finally
);
1389 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1391 /* Prepare for switch statement generation. */
1392 nlabels
= tf
->dest_array
.length ();
1393 return_index
= nlabels
;
1394 eh_index
= return_index
+ tf
->may_return
;
1395 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1396 ndests
= fallthru_index
+ tf
->may_fallthru
;
1398 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1399 finally_label
= create_artificial_label (finally_loc
);
1401 /* We use vec::quick_push on case_label_vec throughout this function,
1402 since we know the size in advance and allocate precisely as muce
1404 case_label_vec
.create (ndests
);
1406 last_case_index
= 0;
1408 /* Begin inserting code for getting to the finally block. Things
1409 are done in this order to correspond to the sequence the code is
1412 if (tf
->may_fallthru
)
1414 x
= gimple_build_assign (finally_tmp
,
1415 build_int_cst (integer_type_node
,
1417 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1419 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1420 last_case
= build_case_label (tmp
, NULL
,
1421 create_artificial_label (tf_loc
));
1422 case_label_vec
.quick_push (last_case
);
1425 x
= gimple_build_label (CASE_LABEL (last_case
));
1426 gimple_seq_add_stmt (&switch_body
, x
);
1428 tmp
= lower_try_finally_fallthru_label (tf
);
1429 x
= gimple_build_goto (tmp
);
1430 gimple_set_location (x
, tf_loc
);
1431 gimple_seq_add_stmt (&switch_body
, x
);
1434 /* For EH_ELSE, emit the exception path (plus resx) now, then
1435 subsequently we only need consider the normal path. */
1440 finally
= gimple_eh_else_e_body (eh_else
);
1441 lower_eh_constructs_1 (state
, &finally
);
1443 emit_post_landing_pad (&eh_seq
, tf
->region
);
1444 gimple_seq_add_seq (&eh_seq
, finally
);
1445 emit_resx (&eh_seq
, tf
->region
);
1448 finally
= gimple_eh_else_n_body (eh_else
);
1450 else if (tf
->may_throw
)
1452 emit_post_landing_pad (&eh_seq
, tf
->region
);
1454 x
= gimple_build_assign (finally_tmp
,
1455 build_int_cst (integer_type_node
, eh_index
));
1456 gimple_seq_add_stmt (&eh_seq
, x
);
1458 x
= gimple_build_goto (finally_label
);
1459 gimple_set_location (x
, tf_loc
);
1460 gimple_seq_add_stmt (&eh_seq
, x
);
1462 tmp
= build_int_cst (integer_type_node
, eh_index
);
1463 last_case
= build_case_label (tmp
, NULL
,
1464 create_artificial_label (tf_loc
));
1465 case_label_vec
.quick_push (last_case
);
1468 x
= gimple_build_label (CASE_LABEL (last_case
));
1469 gimple_seq_add_stmt (&eh_seq
, x
);
1470 emit_resx (&eh_seq
, tf
->region
);
1473 x
= gimple_build_label (finally_label
);
1474 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1476 lower_eh_constructs_1 (state
, &finally
);
1477 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1479 /* Redirect each incoming goto edge. */
1481 qe
= q
+ tf
->goto_queue_active
;
1482 j
= last_case_index
+ tf
->may_return
;
1483 /* Prepare the assignments to finally_tmp that are executed upon the
1484 entrance through a particular edge. */
1487 gimple_seq mod
= NULL
;
1489 unsigned int case_index
;
1493 x
= gimple_build_assign (finally_tmp
,
1494 build_int_cst (integer_type_node
,
1496 gimple_seq_add_stmt (&mod
, x
);
1497 do_return_redirection (q
, finally_label
, mod
);
1498 switch_id
= return_index
;
1502 x
= gimple_build_assign (finally_tmp
,
1503 build_int_cst (integer_type_node
, q
->index
));
1504 gimple_seq_add_stmt (&mod
, x
);
1505 do_goto_redirection (q
, finally_label
, mod
, tf
);
1506 switch_id
= q
->index
;
1509 case_index
= j
+ q
->index
;
1510 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1513 tmp
= build_int_cst (integer_type_node
, switch_id
);
1514 case_lab
= build_case_label (tmp
, NULL
,
1515 create_artificial_label (tf_loc
));
1516 /* We store the cont_stmt in the pointer map, so that we can recover
1517 it in the loop below. */
1519 cont_map
= new hash_map
<tree
, gimple
*>;
1520 cont_map
->put (case_lab
, q
->cont_stmt
);
1521 case_label_vec
.quick_push (case_lab
);
1524 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1528 last_case
= case_label_vec
[j
];
1530 gcc_assert (last_case
);
1531 gcc_assert (cont_map
);
1533 cont_stmt
= *cont_map
->get (last_case
);
1535 x
= gimple_build_label (CASE_LABEL (last_case
));
1536 gimple_seq_add_stmt (&switch_body
, x
);
1537 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1538 maybe_record_in_goto_queue (state
, cont_stmt
);
1543 replace_goto_queue (tf
);
1545 /* Make sure that the last case is the default label, as one is required.
1546 Then sort the labels, which is also required in GIMPLE. */
1547 CASE_LOW (last_case
) = NULL
;
1548 tree tem
= case_label_vec
.pop ();
1549 gcc_assert (tem
== last_case
);
1550 sort_case_labels (case_label_vec
);
1552 /* Build the switch statement, setting last_case to be the default
1554 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1556 gimple_set_location (switch_stmt
, finally_loc
);
1558 /* Need to link SWITCH_STMT after running replace_goto_queue
1559 due to not wanting to process the same goto stmts twice. */
1560 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1561 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1564 /* Decide whether or not we are going to duplicate the finally block.
1565 There are several considerations.
1567 Second, we'd like to prevent egregious code growth. One way to
1568 do this is to estimate the size of the finally block, multiply
1569 that by the number of copies we'd need to make, and compare against
1570 the estimate of the size of the switch machinery we'd have to add. */
1573 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1575 int f_estimate
, sw_estimate
;
1578 /* If there's an EH_ELSE involved, the exception path is separate
1579 and really doesn't come into play for this computation. */
1580 eh_else
= get_eh_else (finally
);
1583 ndests
-= may_throw
;
1584 finally
= gimple_eh_else_n_body (eh_else
);
1589 gimple_stmt_iterator gsi
;
1594 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1596 /* Duplicate __builtin_stack_restore in the hope of eliminating it
1597 on the EH paths and, consequently, useless cleanups. */
1598 gimple
*stmt
= gsi_stmt (gsi
);
1599 if (!is_gimple_debug (stmt
)
1600 && !gimple_clobber_p (stmt
)
1601 && !gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
1607 /* Finally estimate N times, plus N gotos. */
1608 f_estimate
= estimate_num_insns_seq (finally
, &eni_size_weights
);
1609 f_estimate
= (f_estimate
+ 1) * ndests
;
1611 /* Switch statement (cost 10), N variable assignments, N gotos. */
1612 sw_estimate
= 10 + 2 * ndests
;
1614 /* Optimize for size clearly wants our best guess. */
1615 if (optimize_function_for_size_p (cfun
))
1616 return f_estimate
< sw_estimate
;
1618 /* ??? These numbers are completely made up so far. */
1620 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1622 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1625 /* REG is the enclosing region for a possible cleanup region, or the region
1626 itself. Returns TRUE if such a region would be unreachable.
1628 Cleanup regions within a must-not-throw region aren't actually reachable
1629 even if there are throwing stmts within them, because the personality
1630 routine will call terminate before unwinding. */
1633 cleanup_is_dead_in (eh_region reg
)
1635 while (reg
&& reg
->type
== ERT_CLEANUP
)
1637 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1640 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1641 to a sequence of labels and blocks, plus the exception region trees
1642 that record all the magic. This is complicated by the need to
1643 arrange for the FINALLY block to be executed on all exits. */
1646 lower_try_finally (struct leh_state
*state
, gtry
*tp
)
1648 struct leh_tf_state this_tf
;
1649 struct leh_state this_state
;
1651 gimple_seq old_eh_seq
;
1653 /* Process the try block. */
1655 memset (&this_tf
, 0, sizeof (this_tf
));
1656 this_tf
.try_finally_expr
= tp
;
1658 this_tf
.outer
= state
;
1659 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
->cur_region
))
1661 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1662 this_state
.cur_region
= this_tf
.region
;
1666 this_tf
.region
= NULL
;
1667 this_state
.cur_region
= state
->cur_region
;
1670 this_state
.ehp_region
= state
->ehp_region
;
1671 this_state
.tf
= &this_tf
;
1673 old_eh_seq
= eh_seq
;
1676 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1678 /* Determine if the try block is escaped through the bottom. */
1679 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1681 /* Determine if any exceptions are possible within the try block. */
1683 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1684 if (this_tf
.may_throw
)
1685 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1687 /* Determine how many edges (still) reach the finally block. Or rather,
1688 how many destinations are reached by the finally block. Use this to
1689 determine how we process the finally block itself. */
1691 ndests
= this_tf
.dest_array
.length ();
1692 ndests
+= this_tf
.may_fallthru
;
1693 ndests
+= this_tf
.may_return
;
1694 ndests
+= this_tf
.may_throw
;
1696 /* If the FINALLY block is not reachable, dike it out. */
1699 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1700 gimple_try_set_cleanup (tp
, NULL
);
1702 /* If the finally block doesn't fall through, then any destination
1703 we might try to impose there isn't reached either. There may be
1704 some minor amount of cleanup and redirection still needed. */
1705 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1706 lower_try_finally_nofallthru (state
, &this_tf
);
1708 /* We can easily special-case redirection to a single destination. */
1709 else if (ndests
== 1)
1710 lower_try_finally_onedest (state
, &this_tf
);
1711 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1712 gimple_try_cleanup (tp
)))
1713 lower_try_finally_copy (state
, &this_tf
);
1715 lower_try_finally_switch (state
, &this_tf
);
1717 /* If someone requested we add a label at the end of the transformed
1719 if (this_tf
.fallthru_label
)
1721 /* This must be reached only if ndests == 0. */
1722 gimple
*x
= gimple_build_label (this_tf
.fallthru_label
);
1723 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1726 this_tf
.dest_array
.release ();
1727 free (this_tf
.goto_queue
);
1728 if (this_tf
.goto_queue_map
)
1729 delete this_tf
.goto_queue_map
;
1731 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1732 If there was no old eh_seq, then the append is trivially already done. */
1736 eh_seq
= old_eh_seq
;
1739 gimple_seq new_eh_seq
= eh_seq
;
1740 eh_seq
= old_eh_seq
;
1741 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1745 return this_tf
.top_p_seq
;
1748 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1749 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1750 exception region trees that records all the magic. */
1753 lower_catch (struct leh_state
*state
, gtry
*tp
)
1755 eh_region try_region
= NULL
;
1756 struct leh_state this_state
= *state
;
1757 gimple_stmt_iterator gsi
;
1759 gimple_seq new_seq
, cleanup
;
1761 location_t try_catch_loc
= gimple_location (tp
);
1763 if (flag_exceptions
)
1765 try_region
= gen_eh_region_try (state
->cur_region
);
1766 this_state
.cur_region
= try_region
;
1769 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1771 if (!eh_region_may_contain_throw (try_region
))
1772 return gimple_try_eval (tp
);
1775 emit_eh_dispatch (&new_seq
, try_region
);
1776 emit_resx (&new_seq
, try_region
);
1778 this_state
.cur_region
= state
->cur_region
;
1779 this_state
.ehp_region
= try_region
;
1781 /* Add eh_seq from lowering EH in the cleanup sequence after the cleanup
1782 itself, so that e.g. for coverage purposes the nested cleanups don't
1783 appear before the cleanup body. See PR64634 for details. */
1784 gimple_seq old_eh_seq
= eh_seq
;
1788 cleanup
= gimple_try_cleanup (tp
);
1789 for (gsi
= gsi_start (cleanup
);
1797 catch_stmt
= as_a
<gcatch
*> (gsi_stmt (gsi
));
1798 c
= gen_eh_region_catch (try_region
, gimple_catch_types (catch_stmt
));
1800 handler
= gimple_catch_handler (catch_stmt
);
1801 lower_eh_constructs_1 (&this_state
, &handler
);
1803 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1804 x
= gimple_build_label (c
->label
);
1805 gimple_seq_add_stmt (&new_seq
, x
);
1807 gimple_seq_add_seq (&new_seq
, handler
);
1809 if (gimple_seq_may_fallthru (new_seq
))
1812 out_label
= create_artificial_label (try_catch_loc
);
1814 x
= gimple_build_goto (out_label
);
1815 gimple_seq_add_stmt (&new_seq
, x
);
1821 gimple_try_set_cleanup (tp
, new_seq
);
1823 gimple_seq new_eh_seq
= eh_seq
;
1824 eh_seq
= old_eh_seq
;
1825 gimple_seq ret_seq
= frob_into_branch_around (tp
, try_region
, out_label
);
1826 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1830 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1831 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1832 region trees that record all the magic. */
1835 lower_eh_filter (struct leh_state
*state
, gtry
*tp
)
1837 struct leh_state this_state
= *state
;
1838 eh_region this_region
= NULL
;
1842 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1844 if (flag_exceptions
)
1846 this_region
= gen_eh_region_allowed (state
->cur_region
,
1847 gimple_eh_filter_types (inner
));
1848 this_state
.cur_region
= this_region
;
1851 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1853 if (!eh_region_may_contain_throw (this_region
))
1854 return gimple_try_eval (tp
);
1857 this_state
.cur_region
= state
->cur_region
;
1858 this_state
.ehp_region
= this_region
;
1860 emit_eh_dispatch (&new_seq
, this_region
);
1861 emit_resx (&new_seq
, this_region
);
1863 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1864 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1865 gimple_seq_add_stmt (&new_seq
, x
);
1867 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1868 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1870 gimple_try_set_cleanup (tp
, new_seq
);
1872 return frob_into_branch_around (tp
, this_region
, NULL
);
1875 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1876 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1877 plus the exception region trees that record all the magic. */
1880 lower_eh_must_not_throw (struct leh_state
*state
, gtry
*tp
)
1882 struct leh_state this_state
= *state
;
1884 if (flag_exceptions
)
1886 gimple
*inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1887 eh_region this_region
;
1889 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1890 this_region
->u
.must_not_throw
.failure_decl
1891 = gimple_eh_must_not_throw_fndecl (
1892 as_a
<geh_mnt
*> (inner
));
1893 this_region
->u
.must_not_throw
.failure_loc
1894 = LOCATION_LOCUS (gimple_location (tp
));
1896 /* In order to get mangling applied to this decl, we must mark it
1897 used now. Otherwise, pass_ipa_free_lang_data won't think it
1899 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1901 this_state
.cur_region
= this_region
;
1904 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1906 return gimple_try_eval (tp
);
1909 /* Implement a cleanup expression. This is similar to try-finally,
1910 except that we only execute the cleanup block for exception edges. */
1913 lower_cleanup (struct leh_state
*state
, gtry
*tp
)
1915 struct leh_state this_state
= *state
;
1916 eh_region this_region
= NULL
;
1917 struct leh_tf_state fake_tf
;
1919 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1921 if (flag_exceptions
&& !cleanup_dead
)
1923 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1924 this_state
.cur_region
= this_region
;
1927 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1929 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1930 return gimple_try_eval (tp
);
1932 /* Build enough of a try-finally state so that we can reuse
1933 honor_protect_cleanup_actions. */
1934 memset (&fake_tf
, 0, sizeof (fake_tf
));
1935 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1936 fake_tf
.outer
= state
;
1937 fake_tf
.region
= this_region
;
1938 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1939 fake_tf
.may_throw
= true;
1941 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1943 if (fake_tf
.may_throw
)
1945 /* In this case honor_protect_cleanup_actions had nothing to do,
1946 and we should process this normally. */
1947 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1948 result
= frob_into_branch_around (tp
, this_region
,
1949 fake_tf
.fallthru_label
);
1953 /* In this case honor_protect_cleanup_actions did nearly all of
1954 the work. All we have left is to append the fallthru_label. */
1956 result
= gimple_try_eval (tp
);
1957 if (fake_tf
.fallthru_label
)
1959 gimple
*x
= gimple_build_label (fake_tf
.fallthru_label
);
1960 gimple_seq_add_stmt (&result
, x
);
1966 /* Main loop for lowering eh constructs. Also moves gsi to the next
1970 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1974 gimple
*stmt
= gsi_stmt (*gsi
);
1976 switch (gimple_code (stmt
))
1980 tree fndecl
= gimple_call_fndecl (stmt
);
1983 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1984 switch (DECL_FUNCTION_CODE (fndecl
))
1986 case BUILT_IN_EH_POINTER
:
1987 /* The front end may have generated a call to
1988 __builtin_eh_pointer (0) within a catch region. Replace
1989 this zero argument with the current catch region number. */
1990 if (state
->ehp_region
)
1992 tree nr
= build_int_cst (integer_type_node
,
1993 state
->ehp_region
->index
);
1994 gimple_call_set_arg (stmt
, 0, nr
);
1998 /* The user has dome something silly. Remove it. */
1999 rhs
= null_pointer_node
;
2004 case BUILT_IN_EH_FILTER
:
2005 /* ??? This should never appear, but since it's a builtin it
2006 is accessible to abuse by users. Just remove it and
2007 replace the use with the arbitrary value zero. */
2008 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2010 lhs
= gimple_call_lhs (stmt
);
2011 x
= gimple_build_assign (lhs
, rhs
);
2012 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2015 case BUILT_IN_EH_COPY_VALUES
:
2016 /* Likewise this should not appear. Remove it. */
2017 gsi_remove (gsi
, true);
2027 /* If the stmt can throw use a new temporary for the assignment
2028 to a LHS. This makes sure the old value of the LHS is
2029 available on the EH edge. Only do so for statements that
2030 potentially fall through (no noreturn calls e.g.), otherwise
2031 this new assignment might create fake fallthru regions. */
2032 if (stmt_could_throw_p (stmt
)
2033 && gimple_has_lhs (stmt
)
2034 && gimple_stmt_may_fallthru (stmt
)
2035 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2036 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2038 tree lhs
= gimple_get_lhs (stmt
);
2039 tree tmp
= create_tmp_var (TREE_TYPE (lhs
));
2040 gimple
*s
= gimple_build_assign (lhs
, tmp
);
2041 gimple_set_location (s
, gimple_location (stmt
));
2042 gimple_set_block (s
, gimple_block (stmt
));
2043 gimple_set_lhs (stmt
, tmp
);
2044 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2045 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2046 DECL_GIMPLE_REG_P (tmp
) = 1;
2047 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2049 /* Look for things that can throw exceptions, and record them. */
2050 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
2052 record_stmt_eh_region (state
->cur_region
, stmt
);
2053 note_eh_region_may_contain_throw (state
->cur_region
);
2060 maybe_record_in_goto_queue (state
, stmt
);
2064 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2069 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2070 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2071 replace
= lower_try_finally (state
, try_stmt
);
2074 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2077 replace
= gimple_try_eval (try_stmt
);
2078 lower_eh_constructs_1 (state
, &replace
);
2081 switch (gimple_code (x
))
2084 replace
= lower_catch (state
, try_stmt
);
2086 case GIMPLE_EH_FILTER
:
2087 replace
= lower_eh_filter (state
, try_stmt
);
2089 case GIMPLE_EH_MUST_NOT_THROW
:
2090 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2092 case GIMPLE_EH_ELSE
:
2093 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2096 replace
= lower_cleanup (state
, try_stmt
);
2102 /* Remove the old stmt and insert the transformed sequence
2104 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2105 gsi_remove (gsi
, true);
2107 /* Return since we don't want gsi_next () */
2110 case GIMPLE_EH_ELSE
:
2111 /* We should be eliminating this in lower_try_finally et al. */
2115 /* A type, a decl, or some kind of statement that we're not
2116 interested in. Don't walk them. */
2123 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2126 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2128 gimple_stmt_iterator gsi
;
2129 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2130 lower_eh_constructs_2 (state
, &gsi
);
2135 const pass_data pass_data_lower_eh
=
2137 GIMPLE_PASS
, /* type */
2139 OPTGROUP_NONE
, /* optinfo_flags */
2140 TV_TREE_EH
, /* tv_id */
2141 PROP_gimple_lcf
, /* properties_required */
2142 PROP_gimple_leh
, /* properties_provided */
2143 0, /* properties_destroyed */
2144 0, /* todo_flags_start */
2145 0, /* todo_flags_finish */
2148 class pass_lower_eh
: public gimple_opt_pass
2151 pass_lower_eh (gcc::context
*ctxt
)
2152 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2155 /* opt_pass methods: */
2156 virtual unsigned int execute (function
*);
2158 }; // class pass_lower_eh
2161 pass_lower_eh::execute (function
*fun
)
2163 struct leh_state null_state
;
2166 bodyp
= gimple_body (current_function_decl
);
2170 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2171 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2172 memset (&null_state
, 0, sizeof (null_state
));
2174 collect_finally_tree_1 (bodyp
, NULL
);
2175 lower_eh_constructs_1 (&null_state
, &bodyp
);
2176 gimple_set_body (current_function_decl
, bodyp
);
2178 /* We assume there's a return statement, or something, at the end of
2179 the function, and thus ploping the EH sequence afterward won't
2181 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2182 gimple_seq_add_seq (&bodyp
, eh_seq
);
2184 /* We assume that since BODYP already existed, adding EH_SEQ to it
2185 didn't change its value, and we don't have to re-set the function. */
2186 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2188 delete finally_tree
;
2189 finally_tree
= NULL
;
2190 BITMAP_FREE (eh_region_may_contain_throw_map
);
2193 /* If this function needs a language specific EH personality routine
2194 and the frontend didn't already set one do so now. */
2195 if (function_needs_eh_personality (fun
) == eh_personality_lang
2196 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2197 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2198 = lang_hooks
.eh_personality ();
2206 make_pass_lower_eh (gcc::context
*ctxt
)
2208 return new pass_lower_eh (ctxt
);
2211 /* Create the multiple edges from an EH_DISPATCH statement to all of
2212 the possible handlers for its EH region. Return true if there's
2213 no fallthru edge; false if there is. */
2216 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2220 basic_block src
, dst
;
2222 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2223 src
= gimple_bb (stmt
);
2228 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2230 dst
= label_to_block (c
->label
);
2231 make_edge (src
, dst
, 0);
2233 /* A catch-all handler doesn't have a fallthru. */
2234 if (c
->type_list
== NULL
)
2239 case ERT_ALLOWED_EXCEPTIONS
:
2240 dst
= label_to_block (r
->u
.allowed
.label
);
2241 make_edge (src
, dst
, 0);
2251 /* Create the single EH edge from STMT to its nearest landing pad,
2252 if there is such a landing pad within the current function. */
2255 make_eh_edges (gimple
*stmt
)
2257 basic_block src
, dst
;
2261 lp_nr
= lookup_stmt_eh_lp (stmt
);
2265 lp
= get_eh_landing_pad_from_number (lp_nr
);
2266 gcc_assert (lp
!= NULL
);
2268 src
= gimple_bb (stmt
);
2269 dst
= label_to_block (lp
->post_landing_pad
);
2270 make_edge (src
, dst
, EDGE_EH
);
2273 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2274 do not actually perform the final edge redirection.
2276 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2277 we intend to change the destination EH region as well; this means
2278 EH_LANDING_PAD_NR must already be set on the destination block label.
2279 If false, we're being called from generic cfg manipulation code and we
2280 should preserve our place within the region tree. */
2283 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2285 eh_landing_pad old_lp
, new_lp
;
2288 int old_lp_nr
, new_lp_nr
;
2289 tree old_label
, new_label
;
2293 old_bb
= edge_in
->dest
;
2294 old_label
= gimple_block_label (old_bb
);
2295 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2296 gcc_assert (old_lp_nr
> 0);
2297 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2299 throw_stmt
= last_stmt (edge_in
->src
);
2300 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2302 new_label
= gimple_block_label (new_bb
);
2304 /* Look for an existing region that might be using NEW_BB already. */
2305 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2308 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2309 gcc_assert (new_lp
);
2311 /* Unless CHANGE_REGION is true, the new and old landing pad
2312 had better be associated with the same EH region. */
2313 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2318 gcc_assert (!change_region
);
2321 /* Notice when we redirect the last EH edge away from OLD_BB. */
2322 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2323 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2328 /* NEW_LP already exists. If there are still edges into OLD_LP,
2329 there's nothing to do with the EH tree. If there are no more
2330 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2331 If CHANGE_REGION is true, then our caller is expecting to remove
2333 if (e
== NULL
&& !change_region
)
2334 remove_eh_landing_pad (old_lp
);
2338 /* No correct landing pad exists. If there are no more edges
2339 into OLD_LP, then we can simply re-use the existing landing pad.
2340 Otherwise, we have to create a new landing pad. */
2343 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2347 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2348 new_lp
->post_landing_pad
= new_label
;
2349 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2352 /* Maybe move the throwing statement to the new region. */
2353 if (old_lp
!= new_lp
)
2355 remove_stmt_from_eh_lp (throw_stmt
);
2356 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2360 /* Redirect EH edge E to NEW_BB. */
2363 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2365 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2366 return ssa_redirect_edge (edge_in
, new_bb
);
2369 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2370 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2371 The actual edge update will happen in the caller. */
2374 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2376 tree new_lab
= gimple_block_label (new_bb
);
2377 bool any_changed
= false;
2382 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2386 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2388 old_bb
= label_to_block (c
->label
);
2389 if (old_bb
== e
->dest
)
2397 case ERT_ALLOWED_EXCEPTIONS
:
2398 old_bb
= label_to_block (r
->u
.allowed
.label
);
2399 gcc_assert (old_bb
== e
->dest
);
2400 r
->u
.allowed
.label
= new_lab
;
2408 gcc_assert (any_changed
);
2411 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2414 operation_could_trap_helper_p (enum tree_code op
,
2425 case TRUNC_DIV_EXPR
:
2427 case FLOOR_DIV_EXPR
:
2428 case ROUND_DIV_EXPR
:
2429 case EXACT_DIV_EXPR
:
2431 case FLOOR_MOD_EXPR
:
2432 case ROUND_MOD_EXPR
:
2433 case TRUNC_MOD_EXPR
:
2435 if (honor_snans
|| honor_trapv
)
2438 return flag_trapping_math
;
2439 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2448 /* Some floating point comparisons may trap. */
2453 case UNORDERED_EXPR
:
2465 /* These operations don't trap with floating point. */
2473 /* Any floating arithmetic may trap. */
2474 if (fp_operation
&& flag_trapping_math
)
2482 /* Constructing an object cannot trap. */
2486 /* Any floating arithmetic may trap. */
2487 if (fp_operation
&& flag_trapping_math
)
2495 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2496 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2497 type operands that may trap. If OP is a division operator, DIVISOR contains
2498 the value of the divisor. */
2501 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2504 bool honor_nans
= (fp_operation
&& flag_trapping_math
2505 && !flag_finite_math_only
);
2506 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2509 if (TREE_CODE_CLASS (op
) != tcc_comparison
2510 && TREE_CODE_CLASS (op
) != tcc_unary
2511 && TREE_CODE_CLASS (op
) != tcc_binary
2515 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2516 honor_nans
, honor_snans
, divisor
,
2521 /* Returns true if it is possible to prove that the index of
2522 an array access REF (an ARRAY_REF expression) falls into the
2526 in_array_bounds_p (tree ref
)
2528 tree idx
= TREE_OPERAND (ref
, 1);
2531 if (TREE_CODE (idx
) != INTEGER_CST
)
2534 min
= array_ref_low_bound (ref
);
2535 max
= array_ref_up_bound (ref
);
2538 || TREE_CODE (min
) != INTEGER_CST
2539 || TREE_CODE (max
) != INTEGER_CST
)
2542 if (tree_int_cst_lt (idx
, min
)
2543 || tree_int_cst_lt (max
, idx
))
2549 /* Returns true if it is possible to prove that the range of
2550 an array access REF (an ARRAY_RANGE_REF expression) falls
2551 into the array bounds. */
2554 range_in_array_bounds_p (tree ref
)
2556 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2557 tree range_min
, range_max
, min
, max
;
2559 range_min
= TYPE_MIN_VALUE (domain_type
);
2560 range_max
= TYPE_MAX_VALUE (domain_type
);
2563 || TREE_CODE (range_min
) != INTEGER_CST
2564 || TREE_CODE (range_max
) != INTEGER_CST
)
2567 min
= array_ref_low_bound (ref
);
2568 max
= array_ref_up_bound (ref
);
2571 || TREE_CODE (min
) != INTEGER_CST
2572 || TREE_CODE (max
) != INTEGER_CST
)
2575 if (tree_int_cst_lt (range_min
, min
)
2576 || tree_int_cst_lt (max
, range_max
))
2582 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2583 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2584 This routine expects only GIMPLE lhs or rhs input. */
2587 tree_could_trap_p (tree expr
)
2589 enum tree_code code
;
2590 bool fp_operation
= false;
2591 bool honor_trapv
= false;
2592 tree t
, base
, div
= NULL_TREE
;
2597 code
= TREE_CODE (expr
);
2598 t
= TREE_TYPE (expr
);
2602 if (COMPARISON_CLASS_P (expr
))
2603 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2605 fp_operation
= FLOAT_TYPE_P (t
);
2606 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2609 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2610 div
= TREE_OPERAND (expr
, 1);
2611 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2621 case VIEW_CONVERT_EXPR
:
2622 case WITH_SIZE_EXPR
:
2623 expr
= TREE_OPERAND (expr
, 0);
2624 code
= TREE_CODE (expr
);
2627 case ARRAY_RANGE_REF
:
2628 base
= TREE_OPERAND (expr
, 0);
2629 if (tree_could_trap_p (base
))
2631 if (TREE_THIS_NOTRAP (expr
))
2633 return !range_in_array_bounds_p (expr
);
2636 base
= TREE_OPERAND (expr
, 0);
2637 if (tree_could_trap_p (base
))
2639 if (TREE_THIS_NOTRAP (expr
))
2641 return !in_array_bounds_p (expr
);
2643 case TARGET_MEM_REF
:
2645 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2646 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2648 if (TREE_THIS_NOTRAP (expr
))
2650 /* We cannot prove that the access is in-bounds when we have
2651 variable-index TARGET_MEM_REFs. */
2652 if (code
== TARGET_MEM_REF
2653 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2655 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2657 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2658 offset_int off
= mem_ref_offset (expr
);
2659 if (wi::neg_p (off
, SIGNED
))
2661 if (TREE_CODE (base
) == STRING_CST
)
2662 return wi::leu_p (TREE_STRING_LENGTH (base
), off
);
2663 else if (DECL_SIZE_UNIT (base
) == NULL_TREE
2664 || TREE_CODE (DECL_SIZE_UNIT (base
)) != INTEGER_CST
2665 || wi::leu_p (wi::to_offset (DECL_SIZE_UNIT (base
)), off
))
2667 /* Now we are sure the first byte of the access is inside
2674 return !TREE_THIS_NOTRAP (expr
);
2677 return TREE_THIS_VOLATILE (expr
);
2680 t
= get_callee_fndecl (expr
);
2681 /* Assume that calls to weak functions may trap. */
2682 if (!t
|| !DECL_P (t
))
2685 return tree_could_trap_p (t
);
2689 /* Assume that accesses to weak functions may trap, unless we know
2690 they are certainly defined in current TU or in some other
2692 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2694 cgraph_node
*node
= cgraph_node::get (expr
);
2696 node
= node
->function_symbol ();
2697 return !(node
&& node
->in_other_partition
);
2702 /* Assume that accesses to weak vars may trap, unless we know
2703 they are certainly defined in current TU or in some other
2705 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2707 varpool_node
*node
= varpool_node::get (expr
);
2709 node
= node
->ultimate_alias_target ();
2710 return !(node
&& node
->in_other_partition
);
2720 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2721 an assignment or a conditional) may throw. */
2724 stmt_could_throw_1_p (gassign
*stmt
)
2726 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2727 bool honor_nans
= false;
2728 bool honor_snans
= false;
2729 bool fp_operation
= false;
2730 bool honor_trapv
= false;
2735 if (TREE_CODE_CLASS (code
) == tcc_comparison
2736 || TREE_CODE_CLASS (code
) == tcc_unary
2737 || TREE_CODE_CLASS (code
) == tcc_binary
2738 || code
== FMA_EXPR
)
2740 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2741 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2743 t
= gimple_expr_type (stmt
);
2744 fp_operation
= FLOAT_TYPE_P (t
);
2747 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2748 honor_snans
= flag_signaling_nans
!= 0;
2750 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2754 /* First check the LHS. */
2755 if (tree_could_trap_p (gimple_assign_lhs (stmt
)))
2758 /* Check if the main expression may trap. */
2759 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2760 honor_nans
, honor_snans
,
2761 gimple_assign_rhs2 (stmt
),
2766 /* If the expression does not trap, see if any of the individual operands may
2768 for (i
= 1; i
< gimple_num_ops (stmt
); i
++)
2769 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2776 /* Return true if statement STMT could throw an exception. */
2779 stmt_could_throw_p (gimple
*stmt
)
2781 if (!flag_exceptions
)
2784 /* The only statements that can throw an exception are assignments,
2785 conditionals, calls, resx, and asms. */
2786 switch (gimple_code (stmt
))
2792 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2796 if (!cfun
->can_throw_non_call_exceptions
)
2798 gcond
*cond
= as_a
<gcond
*> (stmt
);
2799 tree lhs
= gimple_cond_lhs (cond
);
2800 return operation_could_trap_p (gimple_cond_code (cond
),
2801 FLOAT_TYPE_P (TREE_TYPE (lhs
)),
2806 if (!cfun
->can_throw_non_call_exceptions
2807 || gimple_clobber_p (stmt
))
2809 return stmt_could_throw_1_p (as_a
<gassign
*> (stmt
));
2812 if (!cfun
->can_throw_non_call_exceptions
)
2814 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2822 /* Return true if expression T could throw an exception. */
2825 tree_could_throw_p (tree t
)
2827 if (!flag_exceptions
)
2829 if (TREE_CODE (t
) == MODIFY_EXPR
)
2831 if (cfun
->can_throw_non_call_exceptions
2832 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2834 t
= TREE_OPERAND (t
, 1);
2837 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2838 t
= TREE_OPERAND (t
, 0);
2839 if (TREE_CODE (t
) == CALL_EXPR
)
2840 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2841 if (cfun
->can_throw_non_call_exceptions
)
2842 return tree_could_trap_p (t
);
2846 /* Return true if STMT can throw an exception that is not caught within
2847 the current function (CFUN). */
2850 stmt_can_throw_external (gimple
*stmt
)
2854 if (!stmt_could_throw_p (stmt
))
2857 lp_nr
= lookup_stmt_eh_lp (stmt
);
2861 /* Return true if STMT can throw an exception that is caught within
2862 the current function (CFUN). */
2865 stmt_can_throw_internal (gimple
*stmt
)
2869 if (!stmt_could_throw_p (stmt
))
2872 lp_nr
= lookup_stmt_eh_lp (stmt
);
2876 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2877 remove any entry it might have from the EH table. Return true if
2878 any change was made. */
2881 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple
*stmt
)
2883 if (stmt_could_throw_p (stmt
))
2885 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2888 /* Likewise, but always use the current function. */
2891 maybe_clean_eh_stmt (gimple
*stmt
)
2893 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2896 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2897 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2898 in the table if it should be in there. Return TRUE if a replacement was
2899 done that my require an EH edge purge. */
2902 maybe_clean_or_replace_eh_stmt (gimple
*old_stmt
, gimple
*new_stmt
)
2904 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2908 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2910 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2913 remove_stmt_from_eh_lp (old_stmt
);
2914 if (new_stmt_could_throw
)
2916 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2926 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2927 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2928 operand is the return value of duplicate_eh_regions. */
2931 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple
*new_stmt
,
2932 struct function
*old_fun
, gimple
*old_stmt
,
2933 hash_map
<void *, void *> *map
,
2936 int old_lp_nr
, new_lp_nr
;
2938 if (!stmt_could_throw_p (new_stmt
))
2941 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2944 if (default_lp_nr
== 0)
2946 new_lp_nr
= default_lp_nr
;
2948 else if (old_lp_nr
> 0)
2950 eh_landing_pad old_lp
, new_lp
;
2952 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
2953 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
2954 new_lp_nr
= new_lp
->index
;
2958 eh_region old_r
, new_r
;
2960 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
2961 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
2962 new_lp_nr
= -new_r
->index
;
2965 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2969 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2970 and thus no remapping is required. */
2973 maybe_duplicate_eh_stmt (gimple
*new_stmt
, gimple
*old_stmt
)
2977 if (!stmt_could_throw_p (new_stmt
))
2980 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2984 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2988 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2989 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2990 this only handles handlers consisting of a single call, as that's the
2991 important case for C++: a destructor call for a particular object showing
2992 up in multiple handlers. */
2995 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2997 gimple_stmt_iterator gsi
;
2998 gimple
*ones
, *twos
;
3001 gsi
= gsi_start (oneh
);
3002 if (!gsi_one_before_end_p (gsi
))
3004 ones
= gsi_stmt (gsi
);
3006 gsi
= gsi_start (twoh
);
3007 if (!gsi_one_before_end_p (gsi
))
3009 twos
= gsi_stmt (gsi
);
3011 if (!is_gimple_call (ones
)
3012 || !is_gimple_call (twos
)
3013 || gimple_call_lhs (ones
)
3014 || gimple_call_lhs (twos
)
3015 || gimple_call_chain (ones
)
3016 || gimple_call_chain (twos
)
3017 || !gimple_call_same_target_p (ones
, twos
)
3018 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3021 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3022 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3023 gimple_call_arg (twos
, ai
), 0))
3030 try { A() } finally { try { ~B() } catch { ~A() } }
3031 try { ... } finally { ~A() }
3033 try { A() } catch { ~B() }
3034 try { ~B() ... } finally { ~A() }
3036 This occurs frequently in C++, where A is a local variable and B is a
3037 temporary used in the initializer for A. */
3040 optimize_double_finally (gtry
*one
, gtry
*two
)
3043 gimple_stmt_iterator gsi
;
3046 cleanup
= gimple_try_cleanup (one
);
3047 gsi
= gsi_start (cleanup
);
3048 if (!gsi_one_before_end_p (gsi
))
3051 oneh
= gsi_stmt (gsi
);
3052 if (gimple_code (oneh
) != GIMPLE_TRY
3053 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3056 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3058 gimple_seq seq
= gimple_try_eval (oneh
);
3060 gimple_try_set_cleanup (one
, seq
);
3061 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3062 seq
= copy_gimple_seq_and_replace_locals (seq
);
3063 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3064 gimple_try_set_eval (two
, seq
);
3068 /* Perform EH refactoring optimizations that are simpler to do when code
3069 flow has been lowered but EH structures haven't. */
3072 refactor_eh_r (gimple_seq seq
)
3074 gimple_stmt_iterator gsi
;
3079 gsi
= gsi_start (seq
);
3083 if (gsi_end_p (gsi
))
3086 two
= gsi_stmt (gsi
);
3088 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3089 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3090 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3091 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3092 optimize_double_finally (try_one
, try_two
);
3094 switch (gimple_code (one
))
3097 refactor_eh_r (gimple_try_eval (one
));
3098 refactor_eh_r (gimple_try_cleanup (one
));
3101 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3103 case GIMPLE_EH_FILTER
:
3104 refactor_eh_r (gimple_eh_filter_failure (one
));
3106 case GIMPLE_EH_ELSE
:
3108 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3109 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3110 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3125 const pass_data pass_data_refactor_eh
=
3127 GIMPLE_PASS
, /* type */
3129 OPTGROUP_NONE
, /* optinfo_flags */
3130 TV_TREE_EH
, /* tv_id */
3131 PROP_gimple_lcf
, /* properties_required */
3132 0, /* properties_provided */
3133 0, /* properties_destroyed */
3134 0, /* todo_flags_start */
3135 0, /* todo_flags_finish */
3138 class pass_refactor_eh
: public gimple_opt_pass
3141 pass_refactor_eh (gcc::context
*ctxt
)
3142 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3145 /* opt_pass methods: */
3146 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3147 virtual unsigned int execute (function
*)
3149 refactor_eh_r (gimple_body (current_function_decl
));
3153 }; // class pass_refactor_eh
3158 make_pass_refactor_eh (gcc::context
*ctxt
)
3160 return new pass_refactor_eh (ctxt
);
3163 /* At the end of gimple optimization, we can lower RESX. */
3166 lower_resx (basic_block bb
, gresx
*stmt
,
3167 hash_map
<eh_region
, tree
> *mnt_map
)
3170 eh_region src_r
, dst_r
;
3171 gimple_stmt_iterator gsi
;
3176 lp_nr
= lookup_stmt_eh_lp (stmt
);
3178 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3182 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3183 gsi
= gsi_last_bb (bb
);
3187 /* We can wind up with no source region when pass_cleanup_eh shows
3188 that there are no entries into an eh region and deletes it, but
3189 then the block that contains the resx isn't removed. This can
3190 happen without optimization when the switch statement created by
3191 lower_try_finally_switch isn't simplified to remove the eh case.
3193 Resolve this by expanding the resx node to an abort. */
3195 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3196 x
= gimple_build_call (fn
, 0);
3197 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3199 while (EDGE_COUNT (bb
->succs
) > 0)
3200 remove_edge (EDGE_SUCC (bb
, 0));
3204 /* When we have a destination region, we resolve this by copying
3205 the excptr and filter values into place, and changing the edge
3206 to immediately after the landing pad. */
3214 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3215 the failure decl into a new block, if needed. */
3216 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3218 tree
*slot
= mnt_map
->get (dst_r
);
3221 gimple_stmt_iterator gsi2
;
3223 new_bb
= create_empty_bb (bb
);
3224 add_bb_to_loop (new_bb
, bb
->loop_father
);
3225 lab
= gimple_block_label (new_bb
);
3226 gsi2
= gsi_start_bb (new_bb
);
3228 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3229 x
= gimple_build_call (fn
, 0);
3230 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3231 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3233 mnt_map
->put (dst_r
, lab
);
3238 new_bb
= label_to_block (lab
);
3241 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3242 e
= make_single_succ_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3247 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3249 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3250 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3251 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3252 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3254 /* Update the flags for the outgoing edge. */
3255 e
= single_succ_edge (bb
);
3256 gcc_assert (e
->flags
& EDGE_EH
);
3257 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3258 e
->probability
= profile_probability::always ();
3259 e
->count
= bb
->count
;
3261 /* If there are no more EH users of the landing pad, delete it. */
3262 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3263 if (e
->flags
& EDGE_EH
)
3267 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3268 remove_eh_landing_pad (lp
);
3278 /* When we don't have a destination region, this exception escapes
3279 up the call chain. We resolve this by generating a call to the
3280 _Unwind_Resume library function. */
3282 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3283 with no arguments for C++. Check for that. */
3284 if (src_r
->use_cxa_end_cleanup
)
3286 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3287 x
= gimple_build_call (fn
, 0);
3288 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3292 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3293 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3294 x
= gimple_build_call (fn
, 1, src_nr
);
3295 var
= create_tmp_var (ptr_type_node
);
3296 var
= make_ssa_name (var
, x
);
3297 gimple_call_set_lhs (x
, var
);
3298 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3300 /* When exception handling is delegated to a caller function, we
3301 have to guarantee that shadow memory variables living on stack
3302 will be cleaner before control is given to a parent function. */
3303 if (sanitize_flags_p (SANITIZE_ADDRESS
))
3306 = builtin_decl_implicit (BUILT_IN_ASAN_HANDLE_NO_RETURN
);
3307 gimple
*g
= gimple_build_call (decl
, 0);
3308 gimple_set_location (g
, gimple_location (stmt
));
3309 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
3312 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3313 x
= gimple_build_call (fn
, 1, var
);
3314 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3317 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3320 gsi_remove (&gsi
, true);
3327 const pass_data pass_data_lower_resx
=
3329 GIMPLE_PASS
, /* type */
3331 OPTGROUP_NONE
, /* optinfo_flags */
3332 TV_TREE_EH
, /* tv_id */
3333 PROP_gimple_lcf
, /* properties_required */
3334 0, /* properties_provided */
3335 0, /* properties_destroyed */
3336 0, /* todo_flags_start */
3337 0, /* todo_flags_finish */
3340 class pass_lower_resx
: public gimple_opt_pass
3343 pass_lower_resx (gcc::context
*ctxt
)
3344 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3347 /* opt_pass methods: */
3348 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3349 virtual unsigned int execute (function
*);
3351 }; // class pass_lower_resx
3354 pass_lower_resx::execute (function
*fun
)
3357 bool dominance_invalidated
= false;
3358 bool any_rewritten
= false;
3360 hash_map
<eh_region
, tree
> mnt_map
;
3362 FOR_EACH_BB_FN (bb
, fun
)
3364 gimple
*last
= last_stmt (bb
);
3365 if (last
&& is_gimple_resx (last
))
3367 dominance_invalidated
|=
3368 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3369 any_rewritten
= true;
3373 if (dominance_invalidated
)
3375 free_dominance_info (CDI_DOMINATORS
);
3376 free_dominance_info (CDI_POST_DOMINATORS
);
3379 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3385 make_pass_lower_resx (gcc::context
*ctxt
)
3387 return new pass_lower_resx (ctxt
);
3390 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3394 optimize_clobbers (basic_block bb
)
3396 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3397 bool any_clobbers
= false;
3398 bool seen_stack_restore
= false;
3402 /* Only optimize anything if the bb contains at least one clobber,
3403 ends with resx (checked by caller), optionally contains some
3404 debug stmts or labels, or at most one __builtin_stack_restore
3405 call, and has an incoming EH edge. */
3406 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3408 gimple
*stmt
= gsi_stmt (gsi
);
3409 if (is_gimple_debug (stmt
))
3411 if (gimple_clobber_p (stmt
))
3413 any_clobbers
= true;
3416 if (!seen_stack_restore
3417 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3419 seen_stack_restore
= true;
3422 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3428 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3429 if (e
->flags
& EDGE_EH
)
3433 gsi
= gsi_last_bb (bb
);
3434 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3436 gimple
*stmt
= gsi_stmt (gsi
);
3437 if (!gimple_clobber_p (stmt
))
3439 unlink_stmt_vdef (stmt
);
3440 gsi_remove (&gsi
, true);
3441 release_defs (stmt
);
3445 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3446 internal throw to successor BB. */
3449 sink_clobbers (basic_block bb
)
3453 gimple_stmt_iterator gsi
, dgsi
;
3455 bool any_clobbers
= false;
3458 /* Only optimize if BB has a single EH successor and
3459 all predecessor edges are EH too. */
3460 if (!single_succ_p (bb
)
3461 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3464 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3466 if ((e
->flags
& EDGE_EH
) == 0)
3470 /* And BB contains only CLOBBER stmts before the final
3472 gsi
= gsi_last_bb (bb
);
3473 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3475 gimple
*stmt
= gsi_stmt (gsi
);
3476 if (is_gimple_debug (stmt
))
3478 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3480 if (!gimple_clobber_p (stmt
))
3482 any_clobbers
= true;
3487 edge succe
= single_succ_edge (bb
);
3488 succbb
= succe
->dest
;
3490 /* See if there is a virtual PHI node to take an updated virtual
3493 tree vuse
= NULL_TREE
;
3494 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3495 !gsi_end_p (gpi
); gsi_next (&gpi
))
3497 tree res
= gimple_phi_result (gpi
.phi ());
3498 if (virtual_operand_p (res
))
3506 dgsi
= gsi_after_labels (succbb
);
3507 gsi
= gsi_last_bb (bb
);
3508 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3510 gimple
*stmt
= gsi_stmt (gsi
);
3512 if (is_gimple_debug (stmt
))
3514 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3516 lhs
= gimple_assign_lhs (stmt
);
3517 /* Unfortunately we don't have dominance info updated at this
3518 point, so checking if
3519 dominated_by_p (CDI_DOMINATORS, succbb,
3520 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3521 would be too costly. Thus, avoid sinking any clobbers that
3522 refer to non-(D) SSA_NAMEs. */
3523 if (TREE_CODE (lhs
) == MEM_REF
3524 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3525 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3527 unlink_stmt_vdef (stmt
);
3528 gsi_remove (&gsi
, true);
3529 release_defs (stmt
);
3533 /* As we do not change stmt order when sinking across a
3534 forwarder edge we can keep virtual operands in place. */
3535 gsi_remove (&gsi
, false);
3536 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3538 /* But adjust virtual operands if we sunk across a PHI node. */
3542 imm_use_iterator iter
;
3543 use_operand_p use_p
;
3544 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, vuse
)
3545 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3546 SET_USE (use_p
, gimple_vdef (stmt
));
3547 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
))
3549 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt
)) = 1;
3550 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
) = 0;
3552 /* Adjust the incoming virtual operand. */
3553 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
), gimple_vuse (stmt
));
3554 SET_USE (gimple_vuse_op (stmt
), vuse
);
3556 /* If there isn't a single predecessor but no virtual PHI node
3557 arrange for virtual operands to be renamed. */
3558 else if (gimple_vuse_op (stmt
) != NULL_USE_OPERAND_P
3559 && !single_pred_p (succbb
))
3561 /* In this case there will be no use of the VDEF of this stmt.
3562 ??? Unless this is a secondary opportunity and we have not
3563 removed unreachable blocks yet, so we cannot assert this.
3564 Which also means we will end up renaming too many times. */
3565 SET_USE (gimple_vuse_op (stmt
), gimple_vop (cfun
));
3566 mark_virtual_operands_for_renaming (cfun
);
3567 todo
|= TODO_update_ssa_only_virtuals
;
3574 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3575 we have found some duplicate labels and removed some edges. */
3578 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3580 gimple_stmt_iterator gsi
;
3585 bool redirected
= false;
3587 region_nr
= gimple_eh_dispatch_region (stmt
);
3588 r
= get_eh_region_from_number (region_nr
);
3590 gsi
= gsi_last_bb (src
);
3596 auto_vec
<tree
> labels
;
3597 tree default_label
= NULL
;
3601 hash_set
<tree
> seen_values
;
3603 /* Collect the labels for a switch. Zero the post_landing_pad
3604 field becase we'll no longer have anything keeping these labels
3605 in existence and the optimizer will be free to merge these
3607 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3609 tree tp_node
, flt_node
, lab
= c
->label
;
3610 bool have_label
= false;
3613 tp_node
= c
->type_list
;
3614 flt_node
= c
->filter_list
;
3616 if (tp_node
== NULL
)
3618 default_label
= lab
;
3623 /* Filter out duplicate labels that arise when this handler
3624 is shadowed by an earlier one. When no labels are
3625 attached to the handler anymore, we remove
3626 the corresponding edge and then we delete unreachable
3627 blocks at the end of this pass. */
3628 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3630 tree t
= build_case_label (TREE_VALUE (flt_node
),
3632 labels
.safe_push (t
);
3633 seen_values
.add (TREE_VALUE (flt_node
));
3637 tp_node
= TREE_CHAIN (tp_node
);
3638 flt_node
= TREE_CHAIN (flt_node
);
3643 remove_edge (find_edge (src
, label_to_block (lab
)));
3648 /* Clean up the edge flags. */
3649 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3651 if (e
->flags
& EDGE_FALLTHRU
)
3653 /* If there was no catch-all, use the fallthru edge. */
3654 if (default_label
== NULL
)
3655 default_label
= gimple_block_label (e
->dest
);
3656 e
->flags
&= ~EDGE_FALLTHRU
;
3659 gcc_assert (default_label
!= NULL
);
3661 /* Don't generate a switch if there's only a default case.
3662 This is common in the form of try { A; } catch (...) { B; }. */
3663 if (!labels
.exists ())
3665 e
= single_succ_edge (src
);
3666 e
->flags
|= EDGE_FALLTHRU
;
3670 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3671 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3673 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3674 filter
= make_ssa_name (filter
, x
);
3675 gimple_call_set_lhs (x
, filter
);
3676 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3678 /* Turn the default label into a default case. */
3679 default_label
= build_case_label (NULL
, NULL
, default_label
);
3680 sort_case_labels (labels
);
3682 x
= gimple_build_switch (filter
, default_label
, labels
);
3683 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3688 case ERT_ALLOWED_EXCEPTIONS
:
3690 edge b_e
= BRANCH_EDGE (src
);
3691 edge f_e
= FALLTHRU_EDGE (src
);
3693 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3694 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3696 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3697 filter
= make_ssa_name (filter
, x
);
3698 gimple_call_set_lhs (x
, filter
);
3699 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3701 r
->u
.allowed
.label
= NULL
;
3702 x
= gimple_build_cond (EQ_EXPR
, filter
,
3703 build_int_cst (TREE_TYPE (filter
),
3704 r
->u
.allowed
.filter
),
3705 NULL_TREE
, NULL_TREE
);
3706 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3708 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3709 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3717 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3718 gsi_remove (&gsi
, true);
3724 const pass_data pass_data_lower_eh_dispatch
=
3726 GIMPLE_PASS
, /* type */
3727 "ehdisp", /* name */
3728 OPTGROUP_NONE
, /* optinfo_flags */
3729 TV_TREE_EH
, /* tv_id */
3730 PROP_gimple_lcf
, /* properties_required */
3731 0, /* properties_provided */
3732 0, /* properties_destroyed */
3733 0, /* todo_flags_start */
3734 0, /* todo_flags_finish */
3737 class pass_lower_eh_dispatch
: public gimple_opt_pass
3740 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3741 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3744 /* opt_pass methods: */
3745 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3746 virtual unsigned int execute (function
*);
3748 }; // class pass_lower_eh_dispatch
3751 pass_lower_eh_dispatch::execute (function
*fun
)
3755 bool redirected
= false;
3757 assign_filter_values ();
3759 FOR_EACH_BB_FN (bb
, fun
)
3761 gimple
*last
= last_stmt (bb
);
3764 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3766 redirected
|= lower_eh_dispatch (bb
,
3767 as_a
<geh_dispatch
*> (last
));
3768 flags
|= TODO_update_ssa_only_virtuals
;
3770 else if (gimple_code (last
) == GIMPLE_RESX
)
3772 if (stmt_can_throw_external (last
))
3773 optimize_clobbers (bb
);
3775 flags
|= sink_clobbers (bb
);
3780 delete_unreachable_blocks ();
3787 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3789 return new pass_lower_eh_dispatch (ctxt
);
3792 /* Walk statements, see what regions and, optionally, landing pads
3793 are really referenced.
3795 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3796 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3798 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3801 The caller is responsible for freeing the returned sbitmaps. */
3804 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3806 sbitmap r_reachable
, lp_reachable
;
3808 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3809 gcc_checking_assert (r_reachablep
!= NULL
);
3811 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3812 bitmap_clear (r_reachable
);
3813 *r_reachablep
= r_reachable
;
3815 if (mark_landing_pads
)
3817 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
3818 bitmap_clear (lp_reachable
);
3819 *lp_reachablep
= lp_reachable
;
3822 lp_reachable
= NULL
;
3824 FOR_EACH_BB_FN (bb
, cfun
)
3826 gimple_stmt_iterator gsi
;
3828 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3830 gimple
*stmt
= gsi_stmt (gsi
);
3832 if (mark_landing_pads
)
3834 int lp_nr
= lookup_stmt_eh_lp (stmt
);
3836 /* Negative LP numbers are MUST_NOT_THROW regions which
3837 are not considered BB enders. */
3839 bitmap_set_bit (r_reachable
, -lp_nr
);
3841 /* Positive LP numbers are real landing pads, and BB enders. */
3844 gcc_assert (gsi_one_before_end_p (gsi
));
3845 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
3846 bitmap_set_bit (r_reachable
, region
->index
);
3847 bitmap_set_bit (lp_reachable
, lp_nr
);
3851 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3852 switch (gimple_code (stmt
))
3855 bitmap_set_bit (r_reachable
,
3856 gimple_resx_region (as_a
<gresx
*> (stmt
)));
3858 case GIMPLE_EH_DISPATCH
:
3859 bitmap_set_bit (r_reachable
,
3860 gimple_eh_dispatch_region (
3861 as_a
<geh_dispatch
*> (stmt
)));
3864 if (gimple_call_builtin_p (stmt
, BUILT_IN_EH_COPY_VALUES
))
3865 for (int i
= 0; i
< 2; ++i
)
3867 tree rt
= gimple_call_arg (stmt
, i
);
3868 HOST_WIDE_INT ri
= tree_to_shwi (rt
);
3870 gcc_assert (ri
== (int)ri
);
3871 bitmap_set_bit (r_reachable
, ri
);
3881 /* Remove unreachable handlers and unreachable landing pads. */
3884 remove_unreachable_handlers (void)
3886 sbitmap r_reachable
, lp_reachable
;
3891 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
3895 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3896 dump_eh_tree (dump_file
, cfun
);
3897 fprintf (dump_file
, "Reachable regions: ");
3898 dump_bitmap_file (dump_file
, r_reachable
);
3899 fprintf (dump_file
, "Reachable landing pads: ");
3900 dump_bitmap_file (dump_file
, lp_reachable
);
3905 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3906 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
3908 "Removing unreachable region %d\n",
3912 remove_unreachable_eh_regions (r_reachable
);
3914 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3915 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
3919 "Removing unreachable landing pad %d\n",
3921 remove_eh_landing_pad (lp
);
3926 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3927 dump_eh_tree (dump_file
, cfun
);
3928 fprintf (dump_file
, "\n\n");
3931 sbitmap_free (r_reachable
);
3932 sbitmap_free (lp_reachable
);
3935 verify_eh_tree (cfun
);
3938 /* Remove unreachable handlers if any landing pads have been removed after
3939 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3942 maybe_remove_unreachable_handlers (void)
3947 if (cfun
->eh
== NULL
)
3950 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3951 if (lp
&& lp
->post_landing_pad
)
3953 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3955 remove_unreachable_handlers ();
3961 /* Remove regions that do not have landing pads. This assumes
3962 that remove_unreachable_handlers has already been run, and
3963 that we've just manipulated the landing pads since then.
3965 Preserve regions with landing pads and regions that prevent
3966 exceptions from propagating further, even if these regions
3967 are not reachable. */
3970 remove_unreachable_handlers_no_lp (void)
3973 sbitmap r_reachable
;
3976 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
3978 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3983 if (region
->landing_pads
!= NULL
3984 || region
->type
== ERT_MUST_NOT_THROW
)
3985 bitmap_set_bit (r_reachable
, region
->index
);
3988 && !bitmap_bit_p (r_reachable
, region
->index
))
3990 "Removing unreachable region %d\n",
3994 remove_unreachable_eh_regions (r_reachable
);
3996 sbitmap_free (r_reachable
);
3999 /* Undo critical edge splitting on an EH landing pad. Earlier, we
4000 optimisticaly split all sorts of edges, including EH edges. The
4001 optimization passes in between may not have needed them; if not,
4002 we should undo the split.
4004 Recognize this case by having one EH edge incoming to the BB and
4005 one normal edge outgoing; BB should be empty apart from the
4006 post_landing_pad label.
4008 Note that this is slightly different from the empty handler case
4009 handled by cleanup_empty_eh, in that the actual handler may yet
4010 have actual code but the landing pad has been separated from the
4011 handler. As such, cleanup_empty_eh relies on this transformation
4012 having been done first. */
4015 unsplit_eh (eh_landing_pad lp
)
4017 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4018 gimple_stmt_iterator gsi
;
4021 /* Quickly check the edge counts on BB for singularity. */
4022 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4024 e_in
= single_pred_edge (bb
);
4025 e_out
= single_succ_edge (bb
);
4027 /* Input edge must be EH and output edge must be normal. */
4028 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4031 /* The block must be empty except for the labels and debug insns. */
4032 gsi
= gsi_after_labels (bb
);
4033 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4034 gsi_next_nondebug (&gsi
);
4035 if (!gsi_end_p (gsi
))
4038 /* The destination block must not already have a landing pad
4039 for a different region. */
4040 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4042 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4048 lab
= gimple_label_label (label_stmt
);
4049 lp_nr
= EH_LANDING_PAD_NR (lab
);
4050 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4054 /* The new destination block must not already be a destination of
4055 the source block, lest we merge fallthru and eh edges and get
4056 all sorts of confused. */
4057 if (find_edge (e_in
->src
, e_out
->dest
))
4060 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4061 thought this should have been cleaned up by a phicprop pass, but
4062 that doesn't appear to handle virtuals. Propagate by hand. */
4063 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4065 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4068 gphi
*phi
= gpi
.phi ();
4069 tree lhs
= gimple_phi_result (phi
);
4070 tree rhs
= gimple_phi_arg_def (phi
, 0);
4071 use_operand_p use_p
;
4072 imm_use_iterator iter
;
4074 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4076 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4077 SET_USE (use_p
, rhs
);
4080 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4081 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4083 remove_phi_node (&gpi
, true);
4087 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4088 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4089 lp
->index
, e_out
->dest
->index
);
4091 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4092 a successor edge, humor it. But do the real CFG change with the
4093 predecessor of E_OUT in order to preserve the ordering of arguments
4094 to the PHI nodes in E_OUT->DEST. */
4095 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4096 redirect_edge_pred (e_out
, e_in
->src
);
4097 e_out
->flags
= e_in
->flags
;
4098 e_out
->probability
= e_in
->probability
;
4099 e_out
->count
= e_in
->count
;
4105 /* Examine each landing pad block and see if it matches unsplit_eh. */
4108 unsplit_all_eh (void)
4110 bool changed
= false;
4114 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4116 changed
|= unsplit_eh (lp
);
4121 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4122 to OLD_BB to NEW_BB; return true on success, false on failure.
4124 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4125 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4126 Virtual PHIs may be deleted and marked for renaming. */
4129 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4130 edge old_bb_out
, bool change_region
)
4132 gphi_iterator ngsi
, ogsi
;
4135 bitmap ophi_handled
;
4137 /* The destination block must not be a regular successor for any
4138 of the preds of the landing pad. Thus, avoid turning
4148 which CFG verification would choke on. See PR45172 and PR51089. */
4149 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4150 if (find_edge (e
->src
, new_bb
))
4153 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4154 redirect_edge_var_map_clear (e
);
4156 ophi_handled
= BITMAP_ALLOC (NULL
);
4158 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4159 for the edges we're going to move. */
4160 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4162 gphi
*ophi
, *nphi
= ngsi
.phi ();
4165 nresult
= gimple_phi_result (nphi
);
4166 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4168 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4169 the source ssa_name. */
4171 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4174 if (gimple_phi_result (ophi
) == nop
)
4179 /* If we did find the corresponding PHI, copy those inputs. */
4182 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4183 if (!has_single_use (nop
))
4185 imm_use_iterator imm_iter
;
4186 use_operand_p use_p
;
4188 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4190 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4191 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4192 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4196 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4197 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4202 if ((e
->flags
& EDGE_EH
) == 0)
4204 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4205 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4206 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4209 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4210 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4211 variable is unchanged from input to the block and we can simply
4212 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4216 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4217 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4218 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4222 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4223 we don't know what values from the other edges into NEW_BB to use. */
4224 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4226 gphi
*ophi
= ogsi
.phi ();
4227 tree oresult
= gimple_phi_result (ophi
);
4228 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4232 /* Finally, move the edges and update the PHIs. */
4233 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4234 if (e
->flags
& EDGE_EH
)
4236 /* ??? CFG manipluation routines do not try to update loop
4237 form on edge redirection. Do so manually here for now. */
4238 /* If we redirect a loop entry or latch edge that will either create
4239 a multiple entry loop or rotate the loop. If the loops merge
4240 we may have created a loop with multiple latches.
4241 All of this isn't easily fixed thus cancel the affected loop
4242 and mark the other loop as possibly having multiple latches. */
4243 if (e
->dest
== e
->dest
->loop_father
->header
)
4245 mark_loop_for_removal (e
->dest
->loop_father
);
4246 new_bb
->loop_father
->latch
= NULL
;
4247 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4249 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4250 redirect_edge_succ (e
, new_bb
);
4251 flush_pending_stmts (e
);
4256 BITMAP_FREE (ophi_handled
);
4260 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4261 redirect_edge_var_map_clear (e
);
4262 BITMAP_FREE (ophi_handled
);
4266 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4267 old region to NEW_REGION at BB. */
4270 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4271 eh_landing_pad lp
, eh_region new_region
)
4273 gimple_stmt_iterator gsi
;
4276 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4280 lp
->region
= new_region
;
4281 lp
->next_lp
= new_region
->landing_pads
;
4282 new_region
->landing_pads
= lp
;
4284 /* Delete the RESX that was matched within the empty handler block. */
4285 gsi
= gsi_last_bb (bb
);
4286 unlink_stmt_vdef (gsi_stmt (gsi
));
4287 gsi_remove (&gsi
, true);
4289 /* Clean up E_OUT for the fallthru. */
4290 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4291 e_out
->probability
= profile_probability::always ();
4292 e_out
->count
= e_out
->src
->count
;
4295 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4296 unsplitting than unsplit_eh was prepared to handle, e.g. when
4297 multiple incoming edges and phis are involved. */
4300 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4302 gimple_stmt_iterator gsi
;
4305 /* We really ought not have totally lost everything following
4306 a landing pad label. Given that BB is empty, there had better
4308 gcc_assert (e_out
!= NULL
);
4310 /* The destination block must not already have a landing pad
4311 for a different region. */
4313 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4315 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4320 lab
= gimple_label_label (stmt
);
4321 lp_nr
= EH_LANDING_PAD_NR (lab
);
4322 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4326 /* Attempt to move the PHIs into the successor block. */
4327 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4329 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4331 "Unsplit EH landing pad %d to block %i "
4332 "(via cleanup_empty_eh).\n",
4333 lp
->index
, e_out
->dest
->index
);
4340 /* Return true if edge E_FIRST is part of an empty infinite loop
4341 or leads to such a loop through a series of single successor
4345 infinite_empty_loop_p (edge e_first
)
4347 bool inf_loop
= false;
4350 if (e_first
->dest
== e_first
->src
)
4353 e_first
->src
->aux
= (void *) 1;
4354 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4356 gimple_stmt_iterator gsi
;
4362 e
->dest
->aux
= (void *) 1;
4363 gsi
= gsi_after_labels (e
->dest
);
4364 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4365 gsi_next_nondebug (&gsi
);
4366 if (!gsi_end_p (gsi
))
4369 e_first
->src
->aux
= NULL
;
4370 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4371 e
->dest
->aux
= NULL
;
4376 /* Examine the block associated with LP to determine if it's an empty
4377 handler for its EH region. If so, attempt to redirect EH edges to
4378 an outer region. Return true the CFG was updated in any way. This
4379 is similar to jump forwarding, just across EH edges. */
4382 cleanup_empty_eh (eh_landing_pad lp
)
4384 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4385 gimple_stmt_iterator gsi
;
4387 eh_region new_region
;
4390 bool has_non_eh_pred
;
4394 /* There can be zero or one edges out of BB. This is the quickest test. */
4395 switch (EDGE_COUNT (bb
->succs
))
4401 e_out
= single_succ_edge (bb
);
4407 gsi
= gsi_last_nondebug_bb (bb
);
4408 resx
= gsi_stmt (gsi
);
4409 if (resx
&& is_gimple_resx (resx
))
4411 if (stmt_can_throw_external (resx
))
4412 optimize_clobbers (bb
);
4413 else if (sink_clobbers (bb
))
4417 gsi
= gsi_after_labels (bb
);
4419 /* Make sure to skip debug statements. */
4420 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4421 gsi_next_nondebug (&gsi
);
4423 /* If the block is totally empty, look for more unsplitting cases. */
4424 if (gsi_end_p (gsi
))
4426 /* For the degenerate case of an infinite loop bail out.
4427 If bb has no successors and is totally empty, which can happen e.g.
4428 because of incorrect noreturn attribute, bail out too. */
4430 || infinite_empty_loop_p (e_out
))
4433 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4436 /* The block should consist only of a single RESX statement, modulo a
4437 preceding call to __builtin_stack_restore if there is no outgoing
4438 edge, since the call can be eliminated in this case. */
4439 resx
= gsi_stmt (gsi
);
4440 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4442 gsi_next_nondebug (&gsi
);
4443 resx
= gsi_stmt (gsi
);
4445 if (!is_gimple_resx (resx
))
4447 gcc_assert (gsi_one_nondebug_before_end_p (gsi
));
4449 /* Determine if there are non-EH edges, or resx edges into the handler. */
4450 has_non_eh_pred
= false;
4451 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4452 if (!(e
->flags
& EDGE_EH
))
4453 has_non_eh_pred
= true;
4455 /* Find the handler that's outer of the empty handler by looking at
4456 where the RESX instruction was vectored. */
4457 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4458 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4460 /* If there's no destination region within the current function,
4461 redirection is trivial via removing the throwing statements from
4462 the EH region, removing the EH edges, and allowing the block
4463 to go unreachable. */
4464 if (new_region
== NULL
)
4466 gcc_assert (e_out
== NULL
);
4467 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4468 if (e
->flags
& EDGE_EH
)
4470 gimple
*stmt
= last_stmt (e
->src
);
4471 remove_stmt_from_eh_lp (stmt
);
4479 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4480 to handle the abort and allow the blocks to go unreachable. */
4481 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4483 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4484 if (e
->flags
& EDGE_EH
)
4486 gimple
*stmt
= last_stmt (e
->src
);
4487 remove_stmt_from_eh_lp (stmt
);
4488 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4496 /* Try to redirect the EH edges and merge the PHIs into the destination
4497 landing pad block. If the merge succeeds, we'll already have redirected
4498 all the EH edges. The handler itself will go unreachable if there were
4500 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4503 /* Finally, if all input edges are EH edges, then we can (potentially)
4504 reduce the number of transfers from the runtime by moving the landing
4505 pad from the original region to the new region. This is a win when
4506 we remove the last CLEANUP region along a particular exception
4507 propagation path. Since nothing changes except for the region with
4508 which the landing pad is associated, the PHI nodes do not need to be
4510 if (!has_non_eh_pred
)
4512 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4513 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4514 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4515 lp
->index
, new_region
->index
);
4517 /* ??? The CFG didn't change, but we may have rendered the
4518 old EH region unreachable. Trigger a cleanup there. */
4525 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4526 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4527 remove_eh_landing_pad (lp
);
4531 /* Do a post-order traversal of the EH region tree. Examine each
4532 post_landing_pad block and see if we can eliminate it as empty. */
4535 cleanup_all_empty_eh (void)
4537 bool changed
= false;
4541 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4543 changed
|= cleanup_empty_eh (lp
);
4548 /* Perform cleanups and lowering of exception handling
4549 1) cleanups regions with handlers doing nothing are optimized out
4550 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4551 3) Info about regions that are containing instructions, and regions
4552 reachable via local EH edges is collected
4553 4) Eh tree is pruned for regions no longer necessary.
4555 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4556 Unify those that have the same failure decl and locus.
4560 execute_cleanup_eh_1 (void)
4562 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4563 looking up unreachable landing pads. */
4564 remove_unreachable_handlers ();
4566 /* Watch out for the region tree vanishing due to all unreachable. */
4567 if (cfun
->eh
->region_tree
)
4569 bool changed
= false;
4572 changed
|= unsplit_all_eh ();
4573 changed
|= cleanup_all_empty_eh ();
4577 free_dominance_info (CDI_DOMINATORS
);
4578 free_dominance_info (CDI_POST_DOMINATORS
);
4580 /* We delayed all basic block deletion, as we may have performed
4581 cleanups on EH edges while non-EH edges were still present. */
4582 delete_unreachable_blocks ();
4584 /* We manipulated the landing pads. Remove any region that no
4585 longer has a landing pad. */
4586 remove_unreachable_handlers_no_lp ();
4588 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4597 const pass_data pass_data_cleanup_eh
=
4599 GIMPLE_PASS
, /* type */
4600 "ehcleanup", /* name */
4601 OPTGROUP_NONE
, /* optinfo_flags */
4602 TV_TREE_EH
, /* tv_id */
4603 PROP_gimple_lcf
, /* properties_required */
4604 0, /* properties_provided */
4605 0, /* properties_destroyed */
4606 0, /* todo_flags_start */
4607 0, /* todo_flags_finish */
4610 class pass_cleanup_eh
: public gimple_opt_pass
4613 pass_cleanup_eh (gcc::context
*ctxt
)
4614 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4617 /* opt_pass methods: */
4618 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4619 virtual bool gate (function
*fun
)
4621 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4624 virtual unsigned int execute (function
*);
4626 }; // class pass_cleanup_eh
4629 pass_cleanup_eh::execute (function
*fun
)
4631 int ret
= execute_cleanup_eh_1 ();
4633 /* If the function no longer needs an EH personality routine
4634 clear it. This exposes cross-language inlining opportunities
4635 and avoids references to a never defined personality routine. */
4636 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4637 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4638 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4646 make_pass_cleanup_eh (gcc::context
*ctxt
)
4648 return new pass_cleanup_eh (ctxt
);
4651 /* Verify that BB containing STMT as the last statement, has precisely the
4652 edge that make_eh_edges would create. */
4655 verify_eh_edges (gimple
*stmt
)
4657 basic_block bb
= gimple_bb (stmt
);
4658 eh_landing_pad lp
= NULL
;
4663 lp_nr
= lookup_stmt_eh_lp (stmt
);
4665 lp
= get_eh_landing_pad_from_number (lp_nr
);
4668 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4670 if (e
->flags
& EDGE_EH
)
4674 error ("BB %i has multiple EH edges", bb
->index
);
4686 error ("BB %i can not throw but has an EH edge", bb
->index
);
4692 if (!stmt_could_throw_p (stmt
))
4694 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4698 if (eh_edge
== NULL
)
4700 error ("BB %i is missing an EH edge", bb
->index
);
4704 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4706 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4713 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4716 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4720 basic_block src
, dst
;
4721 bool want_fallthru
= true;
4725 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4726 src
= gimple_bb (stmt
);
4728 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4729 gcc_assert (e
->aux
== NULL
);
4734 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4736 dst
= label_to_block (c
->label
);
4737 e
= find_edge (src
, dst
);
4740 error ("BB %i is missing an edge", src
->index
);
4745 /* A catch-all handler doesn't have a fallthru. */
4746 if (c
->type_list
== NULL
)
4748 want_fallthru
= false;
4754 case ERT_ALLOWED_EXCEPTIONS
:
4755 dst
= label_to_block (r
->u
.allowed
.label
);
4756 e
= find_edge (src
, dst
);
4759 error ("BB %i is missing an edge", src
->index
);
4770 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4772 if (e
->flags
& EDGE_FALLTHRU
)
4774 if (fall_edge
!= NULL
)
4776 error ("BB %i too many fallthru edges", src
->index
);
4785 error ("BB %i has incorrect edge", src
->index
);
4789 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4791 error ("BB %i has incorrect fallthru edge", src
->index
);